diff --git a/content/base/src/nsGenericElement.cpp b/content/base/src/nsGenericElement.cpp
index 7348c02b2d1..7e729f1b7d5 100644
--- a/content/base/src/nsGenericElement.cpp
+++ b/content/base/src/nsGenericElement.cpp
@@ -1226,7 +1226,7 @@ nsGenericElement::TriggerLink(nsIPresContext& aPresContext,
 
       char *absUrl = nsnull;
       char *uriStr = aURLSpec.ToNewCString();
-
+      if (!uriStr) return NS_ERROR_OUT_OF_MEMORY;
       rv = service->MakeAbsolute(uriStr, baseUri, &absUrl);
       nsCRT::free(uriStr);
       NS_RELEASE(baseUri);
diff --git a/content/html/content/src/nsHTMLImageElement.cpp b/content/html/content/src/nsHTMLImageElement.cpp
index a384cce1cfb..797a8d81a59 100644
--- a/content/html/content/src/nsHTMLImageElement.cpp
+++ b/content/html/content/src/nsHTMLImageElement.cpp
@@ -542,10 +542,12 @@ nsHTMLImageElement::SetSrc(const nsString& aSrc)
             if (NS_FAILED(result)) return result;
 
             char *absUrlStr = nsnull;
-            const char *urlSpec = aSrc.GetBuffer();
+            char *urlSpec = aSrc.ToNewCString();
+            if (!urlSpec) return NS_ERROR_OUT_OF_MEMORY;
             result = service->MakeAbsolute(urlSpec, baseUri, &absUrlStr);
             NS_RELEASE(baseUri);
             url = absUrlStr;
+            nsCRT::free(urlSpec);
             delete [] absUrlStr;
 #endif // NECKO
             if (NS_FAILED(result)) {
@@ -567,6 +569,7 @@ nsHTMLImageElement::SetSrc(const nsString& aSrc)
           result = context->StartLoadImage(url, nsnull, specifiedSize,
                                            nsnull, nsnull, nsnull,
                                            nsnull);
+
           NS_RELEASE(context);
         }
         
diff --git a/content/html/style/src/nsCSSParser.cpp b/content/html/style/src/nsCSSParser.cpp
index 37a4a2dd85e..57e58e10bd7 100644
--- a/content/html/style/src/nsCSSParser.cpp
+++ b/content/html/style/src/nsCSSParser.cpp
@@ -2474,11 +2474,12 @@ PRBool CSSParserImpl::ParseURL(PRInt32& aErrorCode, nsCSSValue& aValue)
         }
         if (NS_FAILED(rv)) return PR_FALSE;
         
-        const char* str = tk->mIdent.GetBuffer();
-        if (str == nsnull) return PR_FALSE;
+        char* str = tk->mIdent.ToNewCString();
+        if (!str) return NS_ERROR_OUT_OF_MEMORY;
 
         rv = NS_MakeAbsoluteURI(str, base, absURL);
         NS_RELEASE(base);
+        nsCRT::free(str);
 #else
         rv = NS_MakeAbsoluteURL(mURL, baseURL, tk->mIdent, absURL);
 #endif // NECKO
diff --git a/content/html/style/src/nsCSSStyleSheet.cpp b/content/html/style/src/nsCSSStyleSheet.cpp
index 00c9cded133..29b5e454300 100644
--- a/content/html/style/src/nsCSSStyleSheet.cpp
+++ b/content/html/style/src/nsCSSStyleSheet.cpp
@@ -1485,6 +1485,7 @@ static PRBool SelectorMatches(nsIPresContext* aPresContext,
 
                     char *absUrlStr = nsnull;
                     char *urlSpec = href.ToNewCString();
+                    if (!urlSpec) return NS_ERROR_OUT_OF_MEMORY;
                     rv = service->MakeAbsolute(urlSpec, baseUri, &absUrlStr);
                     nsCRT::free(urlSpec);
                     NS_RELEASE(baseUri);
diff --git a/content/html/style/src/nsHTMLStyleSheet.cpp b/content/html/style/src/nsHTMLStyleSheet.cpp
index 0bf52a8af2b..83632f07aa9 100644
--- a/content/html/style/src/nsHTMLStyleSheet.cpp
+++ b/content/html/style/src/nsHTMLStyleSheet.cpp
@@ -598,9 +598,11 @@ PRInt32 HTMLStyleSheetImpl::RulesMatching(nsIPresContext* aPresContext,
                   if (NS_FAILED(rv)) return 0;
 
                   char *absUrlStr = nsnull;
-                  const char *urlSpec = href.GetBuffer();
+                  char *urlSpec = href.ToNewCString();
+                  if (!urlSpec) return NS_ERROR_OUT_OF_MEMORY;
                   rv = service->MakeAbsolute(urlSpec, baseUri, &absUrlStr);
                   NS_RELEASE(baseUri);
+                  nsCRT::free(urlSpec);
                   absURLSpec = absUrlStr;
                   delete [] absUrlStr;
 #endif // NECKO
diff --git a/content/xml/document/src/nsXMLContentSink.cpp b/content/xml/document/src/nsXMLContentSink.cpp
index 54633aeeef0..f568e7e9977 100644
--- a/content/xml/document/src/nsXMLContentSink.cpp
+++ b/content/xml/document/src/nsXMLContentSink.cpp
@@ -1171,9 +1171,9 @@ nsXMLContentSink::CreateStyleSheetURL(nsIURI** aUrl,
        result = NS_NewURL(aUrl, absURL);
      }
 #else
-     result = NS_MakeAbsoluteURL(docURL, nsnull, aHref, absURL);
+     result = NS_MakeAbsoluteURI(aHref, docURL, absURL);
      if (NS_SUCCEEDED(result)) {
-       result = NS_NewURL(aUrl, absURL);
+       result = NS_NewURI(aUrl, absURL);
      }
 #endif // NECKO
    }
diff --git a/dom/src/base/nsGlobalWindow.cpp b/dom/src/base/nsGlobalWindow.cpp
index d6dc275a0b0..4e830d83d09 100644
--- a/dom/src/base/nsGlobalWindow.cpp
+++ b/dom/src/base/nsGlobalWindow.cpp
@@ -1881,9 +1881,11 @@ GlobalWindowImpl::OpenInternal(JSContext *cx,
     if (NS_FAILED(rv)) return rv;
 
     char *absUrl = nsnull;
-    const char *urlSpec = mURL.GetBuffer();
+    char *urlSpec = mURL.ToNewCString();
+    if (!urlSpec) return NS_ERROR_OUT_OF_MEMORY;
     rv = service->MakeAbsolute(urlSpec, baseUri, &absUrl);
     NS_RELEASE(baseUri);
+    nsCRT::free(urlSpec);
     if (NS_FAILED(rv)) return rv;
     mAbsURL = absUrl;
     delete [] absUrl;
diff --git a/layout/base/src/nsGenericElement.cpp b/layout/base/src/nsGenericElement.cpp
index 7348c02b2d1..7e729f1b7d5 100644
--- a/layout/base/src/nsGenericElement.cpp
+++ b/layout/base/src/nsGenericElement.cpp
@@ -1226,7 +1226,7 @@ nsGenericElement::TriggerLink(nsIPresContext& aPresContext,
 
       char *absUrl = nsnull;
       char *uriStr = aURLSpec.ToNewCString();
-
+      if (!uriStr) return NS_ERROR_OUT_OF_MEMORY;
       rv = service->MakeAbsolute(uriStr, baseUri, &absUrl);
       nsCRT::free(uriStr);
       NS_RELEASE(baseUri);
diff --git a/layout/generic/nsFrameFrame.cpp b/layout/generic/nsFrameFrame.cpp
index bb872c5f933..7f59416e1ee 100644
--- a/layout/generic/nsFrameFrame.cpp
+++ b/layout/generic/nsFrameFrame.cpp
@@ -719,10 +719,12 @@ void TempMakeAbsURL(nsIContent* aContent, nsString& aRelURL, nsString& aAbsURL)
   if (NS_FAILED(result)) return;
 
   char *absUrlStr = nsnull;
-  const char *urlSpec = aRelURL.GetBuffer();
+  char *urlSpec = aRelURL.ToNewCString();
+  if (!urlSpec) return NS_ERROR_OUT_OF_MEMORY;
   result = service->MakeAbsolute(urlSpec, baseUri, &absUrlStr);
   NS_RELEASE(baseUri);
   aAbsURL= absUrlStr;
+  nsCRT::free(urlSpec);
   delete [] absUrlStr;
 #endif // NECKO
   NS_IF_RELEASE(baseURL);
diff --git a/layout/generic/nsImageFrame.cpp b/layout/generic/nsImageFrame.cpp
index 66030baecaf..f4eb098ebce 100644
--- a/layout/generic/nsImageFrame.cpp
+++ b/layout/generic/nsImageFrame.cpp
@@ -681,6 +681,7 @@ nsImageFrame::HandleEvent(nsIPresContext& aPresContext,
 
         char *absUrlStr = nsnull;
         char *baseSpec = src.ToNewCString();
+        if (!baseSpec) return NS_ERROR_OUT_OF_MEMORY;
         rv = service->MakeAbsolute(baseSpec, baseUri, &absUrlStr);
         NS_RELEASE(baseUri);
         absURL = absUrlStr;
diff --git a/layout/generic/nsImageMap.cpp b/layout/generic/nsImageMap.cpp
index a48fe55caa7..0bffac37d0f 100644
--- a/layout/generic/nsImageMap.cpp
+++ b/layout/generic/nsImageMap.cpp
@@ -863,8 +863,10 @@ nsImageMap::IsInside(nscoord aX, nscoord aY,
 
       if ((area->mBase).Length() > 0) {
         // use the area->base as the base uri
-        const char *uriStr = (area->mBase).GetBuffer();
+        char *uriStr = (area->mBase).ToNewCString();
+        if (!uriStr) return NS_ERROR_OUT_OF_MEMORY;
         rv = service->NewURI(uriStr, nsnull, &baseUri);
+        nsCRT::free(uriStr);
       } else {
         rv = aDocURL->QueryInterface(nsIURI::GetIID(), (void**)&baseUri);
       }
@@ -872,6 +874,7 @@ nsImageMap::IsInside(nscoord aX, nscoord aY,
 
       char *absUrlStr = nsnull;
       char *urlSpec = (area->mHREF).ToNewCString();
+      if (!urlSpec) return NS_ERROR_OUT_OF_MEMORY;
       rv = service->MakeAbsolute(urlSpec, baseUri, &absUrlStr);
       NS_RELEASE(baseUri);
       aAbsURL = absUrlStr;
diff --git a/layout/html/base/src/nsHTMLImageLoader.cpp b/layout/html/base/src/nsHTMLImageLoader.cpp
index 68c67f4a6c5..43aa2bfc82d 100644
--- a/layout/html/base/src/nsHTMLImageLoader.cpp
+++ b/layout/html/base/src/nsHTMLImageLoader.cpp
@@ -94,6 +94,7 @@ nsHTMLImageLoader::SetURL(const nsString& aNewSpec)
 
     char *absUrl = nsnull;
     char *urlSpec = mURLSpec.ToNewCString();
+    if (!urlSpec) return NS_ERROR_OUT_OF_MEMORY;
     rv = service->MakeAbsolute(urlSpec, baseUri, &absUrl);
     NS_RELEASE(baseUri);
     nsCRT::free(urlSpec);
diff --git a/layout/html/base/src/nsImageFrame.cpp b/layout/html/base/src/nsImageFrame.cpp
index 66030baecaf..f4eb098ebce 100644
--- a/layout/html/base/src/nsImageFrame.cpp
+++ b/layout/html/base/src/nsImageFrame.cpp
@@ -681,6 +681,7 @@ nsImageFrame::HandleEvent(nsIPresContext& aPresContext,
 
         char *absUrlStr = nsnull;
         char *baseSpec = src.ToNewCString();
+        if (!baseSpec) return NS_ERROR_OUT_OF_MEMORY;
         rv = service->MakeAbsolute(baseSpec, baseUri, &absUrlStr);
         NS_RELEASE(baseUri);
         absURL = absUrlStr;
diff --git a/layout/html/base/src/nsImageMap.cpp b/layout/html/base/src/nsImageMap.cpp
index a48fe55caa7..0bffac37d0f 100644
--- a/layout/html/base/src/nsImageMap.cpp
+++ b/layout/html/base/src/nsImageMap.cpp
@@ -863,8 +863,10 @@ nsImageMap::IsInside(nscoord aX, nscoord aY,
 
       if ((area->mBase).Length() > 0) {
         // use the area->base as the base uri
-        const char *uriStr = (area->mBase).GetBuffer();
+        char *uriStr = (area->mBase).ToNewCString();
+        if (!uriStr) return NS_ERROR_OUT_OF_MEMORY;
         rv = service->NewURI(uriStr, nsnull, &baseUri);
+        nsCRT::free(uriStr);
       } else {
         rv = aDocURL->QueryInterface(nsIURI::GetIID(), (void**)&baseUri);
       }
@@ -872,6 +874,7 @@ nsImageMap::IsInside(nscoord aX, nscoord aY,
 
       char *absUrlStr = nsnull;
       char *urlSpec = (area->mHREF).ToNewCString();
+      if (!urlSpec) return NS_ERROR_OUT_OF_MEMORY;
       rv = service->MakeAbsolute(urlSpec, baseUri, &absUrlStr);
       NS_RELEASE(baseUri);
       aAbsURL = absUrlStr;
diff --git a/layout/html/content/src/nsHTMLImageElement.cpp b/layout/html/content/src/nsHTMLImageElement.cpp
index a384cce1cfb..797a8d81a59 100644
--- a/layout/html/content/src/nsHTMLImageElement.cpp
+++ b/layout/html/content/src/nsHTMLImageElement.cpp
@@ -542,10 +542,12 @@ nsHTMLImageElement::SetSrc(const nsString& aSrc)
             if (NS_FAILED(result)) return result;
 
             char *absUrlStr = nsnull;
-            const char *urlSpec = aSrc.GetBuffer();
+            char *urlSpec = aSrc.ToNewCString();
+            if (!urlSpec) return NS_ERROR_OUT_OF_MEMORY;
             result = service->MakeAbsolute(urlSpec, baseUri, &absUrlStr);
             NS_RELEASE(baseUri);
             url = absUrlStr;
+            nsCRT::free(urlSpec);
             delete [] absUrlStr;
 #endif // NECKO
             if (NS_FAILED(result)) {
@@ -567,6 +569,7 @@ nsHTMLImageElement::SetSrc(const nsString& aSrc)
           result = context->StartLoadImage(url, nsnull, specifiedSize,
                                            nsnull, nsnull, nsnull,
                                            nsnull);
+
           NS_RELEASE(context);
         }
         
diff --git a/layout/html/document/src/nsFrameFrame.cpp b/layout/html/document/src/nsFrameFrame.cpp
index bb872c5f933..7f59416e1ee 100644
--- a/layout/html/document/src/nsFrameFrame.cpp
+++ b/layout/html/document/src/nsFrameFrame.cpp
@@ -719,10 +719,12 @@ void TempMakeAbsURL(nsIContent* aContent, nsString& aRelURL, nsString& aAbsURL)
   if (NS_FAILED(result)) return;
 
   char *absUrlStr = nsnull;
-  const char *urlSpec = aRelURL.GetBuffer();
+  char *urlSpec = aRelURL.ToNewCString();
+  if (!urlSpec) return NS_ERROR_OUT_OF_MEMORY;
   result = service->MakeAbsolute(urlSpec, baseUri, &absUrlStr);
   NS_RELEASE(baseUri);
   aAbsURL= absUrlStr;
+  nsCRT::free(urlSpec);
   delete [] absUrlStr;
 #endif // NECKO
   NS_IF_RELEASE(baseURL);
diff --git a/layout/html/forms/src/nsFormFrame.cpp b/layout/html/forms/src/nsFormFrame.cpp
index 9026366ed6d..98082d7730b 100644
--- a/layout/html/forms/src/nsFormFrame.cpp
+++ b/layout/html/forms/src/nsFormFrame.cpp
@@ -549,9 +549,11 @@ nsFormFrame::OnSubmit(nsIPresContext* aPresContext, nsIFrame* aFrame)
     if (NS_FAILED(result)) return result;
 
     char *absUrlStr = nsnull;
-    const char *urlSpec = href.GetBuffer();
+    char *urlSpec = href.ToNewCString();
+    if (!urlSpec) return NS_ERROR_OUT_OF_MEMORY;
     result = service->MakeAbsolute(urlSpec, baseUri, &absUrlStr);
     NS_RELEASE(baseUri);
+    nsCRT::free(urlSpec);
     absURLSpec = absUrlStr;
     delete [] absUrlStr;
 #endif // NECKO
diff --git a/layout/html/style/src/nsCSSParser.cpp b/layout/html/style/src/nsCSSParser.cpp
index 37a4a2dd85e..57e58e10bd7 100644
--- a/layout/html/style/src/nsCSSParser.cpp
+++ b/layout/html/style/src/nsCSSParser.cpp
@@ -2474,11 +2474,12 @@ PRBool CSSParserImpl::ParseURL(PRInt32& aErrorCode, nsCSSValue& aValue)
         }
         if (NS_FAILED(rv)) return PR_FALSE;
         
-        const char* str = tk->mIdent.GetBuffer();
-        if (str == nsnull) return PR_FALSE;
+        char* str = tk->mIdent.ToNewCString();
+        if (!str) return NS_ERROR_OUT_OF_MEMORY;
 
         rv = NS_MakeAbsoluteURI(str, base, absURL);
         NS_RELEASE(base);
+        nsCRT::free(str);
 #else
         rv = NS_MakeAbsoluteURL(mURL, baseURL, tk->mIdent, absURL);
 #endif // NECKO
diff --git a/layout/html/style/src/nsCSSStyleSheet.cpp b/layout/html/style/src/nsCSSStyleSheet.cpp
index 00c9cded133..29b5e454300 100644
--- a/layout/html/style/src/nsCSSStyleSheet.cpp
+++ b/layout/html/style/src/nsCSSStyleSheet.cpp
@@ -1485,6 +1485,7 @@ static PRBool SelectorMatches(nsIPresContext* aPresContext,
 
                     char *absUrlStr = nsnull;
                     char *urlSpec = href.ToNewCString();
+                    if (!urlSpec) return NS_ERROR_OUT_OF_MEMORY;
                     rv = service->MakeAbsolute(urlSpec, baseUri, &absUrlStr);
                     nsCRT::free(urlSpec);
                     NS_RELEASE(baseUri);
diff --git a/layout/html/style/src/nsHTMLStyleSheet.cpp b/layout/html/style/src/nsHTMLStyleSheet.cpp
index 0bf52a8af2b..83632f07aa9 100644
--- a/layout/html/style/src/nsHTMLStyleSheet.cpp
+++ b/layout/html/style/src/nsHTMLStyleSheet.cpp
@@ -598,9 +598,11 @@ PRInt32 HTMLStyleSheetImpl::RulesMatching(nsIPresContext* aPresContext,
                   if (NS_FAILED(rv)) return 0;
 
                   char *absUrlStr = nsnull;
-                  const char *urlSpec = href.GetBuffer();
+                  char *urlSpec = href.ToNewCString();
+                  if (!urlSpec) return NS_ERROR_OUT_OF_MEMORY;
                   rv = service->MakeAbsolute(urlSpec, baseUri, &absUrlStr);
                   NS_RELEASE(baseUri);
+                  nsCRT::free(urlSpec);
                   absURLSpec = absUrlStr;
                   delete [] absUrlStr;
 #endif // NECKO
diff --git a/layout/style/nsCSSParser.cpp b/layout/style/nsCSSParser.cpp
index 37a4a2dd85e..57e58e10bd7 100644
--- a/layout/style/nsCSSParser.cpp
+++ b/layout/style/nsCSSParser.cpp
@@ -2474,11 +2474,12 @@ PRBool CSSParserImpl::ParseURL(PRInt32& aErrorCode, nsCSSValue& aValue)
         }
         if (NS_FAILED(rv)) return PR_FALSE;
         
-        const char* str = tk->mIdent.GetBuffer();
-        if (str == nsnull) return PR_FALSE;
+        char* str = tk->mIdent.ToNewCString();
+        if (!str) return NS_ERROR_OUT_OF_MEMORY;
 
         rv = NS_MakeAbsoluteURI(str, base, absURL);
         NS_RELEASE(base);
+        nsCRT::free(str);
 #else
         rv = NS_MakeAbsoluteURL(mURL, baseURL, tk->mIdent, absURL);
 #endif // NECKO
diff --git a/layout/style/nsCSSStyleSheet.cpp b/layout/style/nsCSSStyleSheet.cpp
index 00c9cded133..29b5e454300 100644
--- a/layout/style/nsCSSStyleSheet.cpp
+++ b/layout/style/nsCSSStyleSheet.cpp
@@ -1485,6 +1485,7 @@ static PRBool SelectorMatches(nsIPresContext* aPresContext,
 
                     char *absUrlStr = nsnull;
                     char *urlSpec = href.ToNewCString();
+                    if (!urlSpec) return NS_ERROR_OUT_OF_MEMORY;
                     rv = service->MakeAbsolute(urlSpec, baseUri, &absUrlStr);
                     nsCRT::free(urlSpec);
                     NS_RELEASE(baseUri);
diff --git a/layout/style/nsHTMLStyleSheet.cpp b/layout/style/nsHTMLStyleSheet.cpp
index 0bf52a8af2b..83632f07aa9 100644
--- a/layout/style/nsHTMLStyleSheet.cpp
+++ b/layout/style/nsHTMLStyleSheet.cpp
@@ -598,9 +598,11 @@ PRInt32 HTMLStyleSheetImpl::RulesMatching(nsIPresContext* aPresContext,
                   if (NS_FAILED(rv)) return 0;
 
                   char *absUrlStr = nsnull;
-                  const char *urlSpec = href.GetBuffer();
+                  char *urlSpec = href.ToNewCString();
+                  if (!urlSpec) return NS_ERROR_OUT_OF_MEMORY;
                   rv = service->MakeAbsolute(urlSpec, baseUri, &absUrlStr);
                   NS_RELEASE(baseUri);
+                  nsCRT::free(urlSpec);
                   absURLSpec = absUrlStr;
                   delete [] absUrlStr;
 #endif // NECKO
diff --git a/layout/xml/document/src/nsXMLContentSink.cpp b/layout/xml/document/src/nsXMLContentSink.cpp
index 54633aeeef0..f568e7e9977 100644
--- a/layout/xml/document/src/nsXMLContentSink.cpp
+++ b/layout/xml/document/src/nsXMLContentSink.cpp
@@ -1171,9 +1171,9 @@ nsXMLContentSink::CreateStyleSheetURL(nsIURI** aUrl,
        result = NS_NewURL(aUrl, absURL);
      }
 #else
-     result = NS_MakeAbsoluteURL(docURL, nsnull, aHref, absURL);
+     result = NS_MakeAbsoluteURI(aHref, docURL, absURL);
      if (NS_SUCCEEDED(result)) {
-       result = NS_NewURL(aUrl, absURL);
+       result = NS_NewURI(aUrl, absURL);
      }
 #endif // NECKO
    }
diff --git a/webshell/tests/viewer/nsWebCrawler.cpp b/webshell/tests/viewer/nsWebCrawler.cpp
index 2f1df1a1614..5f3cc51205d 100644
--- a/webshell/tests/viewer/nsWebCrawler.cpp
+++ b/webshell/tests/viewer/nsWebCrawler.cpp
@@ -685,15 +685,18 @@ nsWebCrawler::FindURLsIn(nsIDocument* aDocument, nsIContent* aNode)
     nsIURI *baseUri = nsnull;
 
     if (base.Length() > 0) {
-        const char *uriStr = base.GetBuffer();
+        char *uriStr = base.ToNewCString();
+        if (!uriStr) return NS_ERROR_OUT_OF_MEMORY;
         rv = service->NewURI(uriStr, nsnull, &baseUri);
+        nsCRT::free(uriStr);
     } else {
         rv = docURL->QueryInterface(nsIURI::GetIID(), (void**)&baseUri);
     }
     if (NS_FAILED(rv)) return;
 
     char *absUrlStr = nsnull;
-    const char *urlSpec = src.GetBuffer();
+    char *urlSpec = src.ToNewCString();
+    if (!urlSpec) return NS_ERROR_OUT_OF_MEMORY;
     rv = service->MakeAbsolute(urlSpec, baseUri, &absUrlStr);
     NS_RELEASE(baseUri);
     absURLSpec = absUrlStr;