diff --git a/netwerk/base/public/nsITransport.idl b/netwerk/base/public/nsITransport.idl
index bc4e41219904..2acbea2e33a0 100644
--- a/netwerk/base/public/nsITransport.idl
+++ b/netwerk/base/public/nsITransport.idl
@@ -48,7 +48,7 @@ interface nsITransport : nsISupports
      * Open an input stream on this transport.
      *
      * @param offset - read starting at this offset
-     * @param count  - read this many bytes (pass ULONG_MAX if unlimited)
+     * @param count  - read this many bytes (pass PRUint32(-1) if unlimited)
      * @param flags  - optional transport specific flags
      */
     nsIInputStream openInputStream(in unsigned long offset,
@@ -59,7 +59,7 @@ interface nsITransport : nsISupports
      * Open an output stream on this transport.
      *
      * @param offset - write starting at this offset
-     * @param count  - write no more than this many bytes (pass ULONG_MAX if unlimited)
+     * @param count  - write no more than this many bytes (pass PRUint32(-1) if unlimited)
      * @param flags  - optional transport specific flags
      */
     nsIOutputStream openOutputStream(in unsigned long offset,
@@ -72,7 +72,7 @@ interface nsITransport : nsISupports
      * @param listener - notify this listener when data is available
      * @param ctxt     - opaque parameter passed to listener methods
      * @param offset   - read starting at this offset
-     * @param count    - read this many bytes (pass ULONG_MAX if unlimited)
+     * @param count    - read this many bytes (pass PRUint32(-1) if unlimited)
      * @param flags    - optional transport specific flags
      */
     nsIRequest asyncRead(in nsIStreamListener listener,
@@ -87,7 +87,7 @@ interface nsITransport : nsISupports
      * @param provider - notify this provider when data can be written
      * @param ctxt     - opaque parameter passed to provider methods
      * @param offset   - write starting at this offset
-     * @param count    - write no more than this many bytes (pass ULONG_MAX if unlimited)
+     * @param count    - write no more than this many bytes (pass PRUint32(-1) if unlimited)
      * @param flags    - optional transport specific flags
      */
     nsIRequest asyncWrite(in nsIStreamProvider provider,
diff --git a/netwerk/base/src/nsFileTransport.cpp b/netwerk/base/src/nsFileTransport.cpp
index 126b9579f627..7d8ba5cc6450 100644
--- a/netwerk/base/src/nsFileTransport.cpp
+++ b/netwerk/base/src/nsFileTransport.cpp
@@ -414,7 +414,7 @@ nsFileTransport::OpenInputStream(PRUint32 aTransferOffset,
                                  nsIInputStream **aResult)
 {
     NS_ENSURE_ARG_POINTER(aResult);
-    NS_ASSERTION(aTransferCount == ULONG_MAX, "need to wrap input stream in one that truncates");
+    NS_ASSERTION(aTransferCount == PRUint32(-1), "need to wrap input stream in one that truncates");
     
     nsresult rv = mStreamIO->GetInputStream(aResult);
     if (NS_SUCCEEDED(rv) && aTransferOffset) {
@@ -434,7 +434,7 @@ nsFileTransport::OpenOutputStream(PRUint32 aTransferOffset,
                                   nsIOutputStream **aResult)
 {
     NS_ENSURE_ARG_POINTER(aResult);
-    NS_ASSERTION(aTransferCount == ULONG_MAX, "need to wrap output stream in one that truncates");
+    NS_ASSERTION(aTransferCount == PRUint32(-1), "need to wrap output stream in one that truncates");
     
     nsresult rv = mStreamIO->GetOutputStream(aResult);
     if (NS_SUCCEEDED(rv) && aTransferOffset) {
diff --git a/netwerk/protocol/about/src/nsAboutCacheEntry.cpp b/netwerk/protocol/about/src/nsAboutCacheEntry.cpp
index 55ae75f5c952..aacf7ca06e88 100644
--- a/netwerk/protocol/about/src/nsAboutCacheEntry.cpp
+++ b/netwerk/protocol/about/src/nsAboutCacheEntry.cpp
@@ -75,7 +75,7 @@ nsAboutCacheEntry::OnCacheEntryAvailable(nsICacheEntryDescriptor *descriptor,
     nsresult rv;
 
     // Init: (block size, maximum length)
-    rv = NS_NewStorageStream(256, ULONG_MAX, getter_AddRefs(storageStream));
+    rv = NS_NewStorageStream(256, PRUint32(-1), getter_AddRefs(storageStream));
     if (NS_FAILED(rv)) return rv;
 
     rv = storageStream->GetOutputStream(0, getter_AddRefs(outputStream));
diff --git a/netwerk/protocol/ftp/src/nsFtpConnectionThread.cpp b/netwerk/protocol/ftp/src/nsFtpConnectionThread.cpp
index fc784fbd24a4..0f47f1d73b96 100644
--- a/netwerk/protocol/ftp/src/nsFtpConnectionThread.cpp
+++ b/netwerk/protocol/ftp/src/nsFtpConnectionThread.cpp
@@ -156,7 +156,7 @@ DataRequestForwarder::DelayedOnStartRequest(nsIRequest *request, nsISupports *ct
             NS_ASSERTION(0, "Could not create cache transport.");
             return rv;
         }
-        rv = transport->OpenOutputStream(0, (PRUint32) ULONG_MAX, 0, getter_AddRefs(mCacheOutputStream));
+        rv = transport->OpenOutputStream(0, PRUint32(-1), 0, getter_AddRefs(mCacheOutputStream));
         
         if (NS_FAILED(rv)) {
             NS_ASSERTION(0, "Could not create cache output stream.");
@@ -1521,13 +1521,13 @@ nsFtpState::S_list() {
             NS_ASSERTION(0, "Could not create cache transport.");
             return rv;
         }
-        rv = transport->AsyncRead(forwarder, nsnull, 0, ULONG_MAX, 0, getter_AddRefs(mDPipeRequest));
+        rv = transport->AsyncRead(forwarder, nsnull, 0, PRUint32(-1), 0, getter_AddRefs(mDPipeRequest));
         return rv;
     }
 
     (void) forwarder->SetCacheEntryDescriptor(mCacheEntry);
 #endif
-    rv = mDPipe->AsyncRead(forwarder, nsnull, 0, ULONG_MAX, 0, getter_AddRefs(mDPipeRequest));
+    rv = mDPipe->AsyncRead(forwarder, nsnull, 0, PRUint32(-1), 0, getter_AddRefs(mDPipeRequest));
     NS_RELEASE(forwarder); // let the transport worry about this objects lifespan
     return rv;
 }
@@ -1560,7 +1560,7 @@ nsFtpState::S_retr() {
         PR_LOG(gFTPLog, PR_LOG_DEBUG, ("(%x) forwarder->Init failed (rv=%x)\n", this, rv));
         return rv;
     }
-    rv = mDPipe->AsyncRead(forwarder, nsnull, 0, ULONG_MAX, 0, getter_AddRefs(mDPipeRequest));    
+    rv = mDPipe->AsyncRead(forwarder, nsnull, 0, PRUint32(-1), 0, getter_AddRefs(mDPipeRequest));    
     NS_RELEASE(forwarder); // let the transport worry about this objects lifespan
     
     return rv;
@@ -2293,7 +2293,7 @@ nsFtpState::CreateTransport(const char * host, PRInt32 port, PRUint32 bufferSegm
         }
     }
     
-    return sts->CreateTransport(host, port, nsnull, ULONG_MAX,
+    return sts->CreateTransport(host, port, nsnull, PRUint32(-1),
                                 bufferSegmentSize,
                                 bufferMaxSize,
                                 o_pTrans);
diff --git a/netwerk/protocol/http/src/nsHTTPChannel.cpp b/netwerk/protocol/http/src/nsHTTPChannel.cpp
index ccf917e477a3..b3b0dc48dd9e 100644
--- a/netwerk/protocol/http/src/nsHTTPChannel.cpp
+++ b/netwerk/protocol/http/src/nsHTTPChannel.cpp
@@ -1302,7 +1302,7 @@ nsHTTPChannel::ReadFromCache()
     // Pump the cache data downstream
     LOG(("\n>>>> Reading from Cache <<<<\n"));
     rv = mCacheTransport->AsyncRead(listener, mResponseContext,
-                                    0, ULONG_MAX, 0,
+                                    0, PRUint32(-1), 0,
                                     getter_AddRefs(mCacheReadRequest));
 
     NS_RELEASE(listener);
@@ -1429,7 +1429,7 @@ nsHTTPChannel::CacheReceivedResponse(nsIStreamListener *aListener,
     if (NS_FAILED(rv)) return rv;
 
     nsCOMPtr<nsIOutputStream> out;
-    rv = mCacheTransport->OpenOutputStream(0, ULONG_MAX, 0, getter_AddRefs(out));
+    rv = mCacheTransport->OpenOutputStream(0, PRUint32(-1), 0, getter_AddRefs(out));
     if (NS_FAILED(rv)) return rv;
 
     // XXX disk cache does not support overlapped i/o yet
@@ -3082,7 +3082,7 @@ nsHTTPChannel::ProcessNotModifiedResponse(nsIStreamListener *aListener)
 #ifdef MOZ_NEW_CACHE
     LOG((">>>> Reading from Cache <<<<\n"));
     rv = mCacheTransport->AsyncRead(cacheListener, mResponseContext,
-                                    0, ULONG_MAX, 0,
+                                    0, PRUint32(-1), 0,
                                     getter_AddRefs(mCacheReadRequest));
 #else
     rv = mCacheChannel->AsyncOpen(cacheListener, mResponseContext);