diff --git a/content/xul/content/src/nsXULElement.cpp b/content/xul/content/src/nsXULElement.cpp
index 52adf122a59..0f53821c771 100644
--- a/content/xul/content/src/nsXULElement.cpp
+++ b/content/xul/content/src/nsXULElement.cpp
@@ -4632,7 +4632,7 @@ nsXULPrototypeScript::Compile(const PRUnichar* aText,
                                 scopeObject,
                                 principal,
                                 urlspec,
-                                aLineNo,
+                                PRUint32(aLineNo),
                                 mLangVersion,
                                 (void**) &mScriptObject);
 
diff --git a/rdf/content/src/nsXULElement.cpp b/rdf/content/src/nsXULElement.cpp
index 52adf122a59..0f53821c771 100644
--- a/rdf/content/src/nsXULElement.cpp
+++ b/rdf/content/src/nsXULElement.cpp
@@ -4632,7 +4632,7 @@ nsXULPrototypeScript::Compile(const PRUnichar* aText,
                                 scopeObject,
                                 principal,
                                 urlspec,
-                                aLineNo,
+                                PRUint32(aLineNo),
                                 mLangVersion,
                                 (void**) &mScriptObject);