diff --git a/browser/installer/package-manifest.in b/browser/installer/package-manifest.in
index e513db71c54b..13c58000c65d 100644
--- a/browser/installer/package-manifest.in
+++ b/browser/installer/package-manifest.in
@@ -363,7 +363,9 @@
 @BINPATH@/@PREF_DIR@/firefox.js
 @BINPATH@/@PREF_DIR@/firefox-branding.js
 @BINPATH@/@PREF_DIR@/channel-prefs.js
-@BINPATH@/greprefs.js
+@BINPATH@/greprefs/all.js
+@BINPATH@/greprefs/security-prefs.js
+@BINPATH@/greprefs/xpinstall.js
 @BINPATH@/defaults/autoconfig/platform.js
 @BINPATH@/defaults/autoconfig/prefcalls.js
 
diff --git a/browser/installer/removed-files.in b/browser/installer/removed-files.in
index 82be8463764c..125b30f4ac33 100644
--- a/browser/installer/removed-files.in
+++ b/browser/installer/removed-files.in
@@ -780,9 +780,6 @@ components/xuldoc.xpt
 components/xultmpl.xpt
 components/zipwriter.xpt
 components/firefox.xpt
-greprefs/all.js
-greprefs/security-prefs.js
-greprefs/xpinstall.js
 run-mozilla.sh
 firefox
 dependentlibs.list
@@ -813,4 +810,4 @@ install.rdf
 @DLL_PREFIX@jsj@DLL_SUFFIX@
 #ifdef XP_WIN
 components/brwsrcmp.dll
-#endif
+#endif
\ No newline at end of file
diff --git a/modules/libpref/src/Makefile.in b/modules/libpref/src/Makefile.in
index b7836f0385ea..450c9fd40425 100644
--- a/modules/libpref/src/Makefile.in
+++ b/modules/libpref/src/Makefile.in
@@ -72,6 +72,8 @@ ifdef WINCE
 DEFINES += -DWINCE=1
 endif
 
+PREF_JS_EXPORTS	= $(srcdir)/init/all.js
+
 EXTRA_DSO_LDOPTS = \
 		$(LIBS_DIR) \
 		$(MOZ_COMPONENT_LIBS) \
@@ -80,13 +82,9 @@ EXTRA_DSO_LDOPTS = \
 include $(topsrcdir)/config/rules.mk
 
 GARBAGE		+= $(addprefix $(DIST)/bin/defaults/pref/, \
-			mailnews.js editor.js \
+			all.js mailnews.js editor.js \
 			aix.js beos.js unix.js winpref.js os2prefs.js openvms.js photon.js)
 
-GARBAGE		+= greprefs.js
-
-GREPREF_FILES = $(topsrcdir)/xpinstall/public/xpinstall.js $(topsrcdir)/netwerk/base/public/security-prefs.js $(srcdir)/init/all.js
-
 # Optimizer bug with GCC 3.2.2 on OS/2
 ifeq ($(OS_ARCH), OS2)
 nsPrefService.$(OBJ_SUFFIX): nsPrefService.cpp
@@ -94,10 +92,3 @@ nsPrefService.$(OBJ_SUFFIX): nsPrefService.cpp
 	@$(MAKE_DEPS_AUTO_CXX)
 	$(ELOG) $(CCC) $(OUTOPTION)$@ -c $(COMPILE_CXXFLAGS:-O2=-O1) $(_VPATH_SRCS)
 endif
-
-
-greprefs.js: $(GREPREF_FILES)
-	$(PYTHON) $(topsrcdir)/config/Preprocessor.py $(PREF_PPFLAGS) $(DEFINES) $(ACDEFINES) $(XULPPFLAGS) $^ > $@
-
-libs:: greprefs.js
-	$(INSTALL) $^ $(DIST)/bin/
diff --git a/modules/libpref/src/nsPrefService.cpp b/modules/libpref/src/nsPrefService.cpp
index eef72eea44f1..79791f39328a 100644
--- a/modules/libpref/src/nsPrefService.cpp
+++ b/modules/libpref/src/nsPrefService.cpp
@@ -464,8 +464,8 @@ static nsresult openPrefFile(nsIFile* aFile)
   if (NS_FAILED(rv)) 
     return rv;        
 
-  PRUint32 fileSize;
-  rv = inStr->Available(&fileSize);
+  PRInt64 fileSize;
+  rv = aFile->GetFileSize(&fileSize);
   if (NS_FAILED(rv))
     return rv;
 
@@ -640,19 +640,18 @@ static nsresult pref_LoadPrefsInDirList(const char *listId)
 static nsresult pref_InitInitialObjects()
 {
   nsCOMPtr<nsIFile> aFile;
-  nsCOMPtr<nsIFile> greprefsFile;
   nsCOMPtr<nsIFile> defaultPrefDir;
   nsresult          rv;
 
   // first we parse the GRE default prefs. This also works if we're not using a GRE, 
 
-  rv = NS_GetSpecialDirectory(NS_GRE_DIR, getter_AddRefs(greprefsFile));
+  rv = NS_GetSpecialDirectory(NS_GRE_DIR, getter_AddRefs(defaultPrefDir));
   NS_ENSURE_SUCCESS(rv, rv);
 
-  rv = greprefsFile->AppendNative(NS_LITERAL_CSTRING("greprefs.js"));
+  rv = defaultPrefDir->AppendNative(NS_LITERAL_CSTRING("greprefs"));
   NS_ENSURE_SUCCESS(rv, rv);
 
-  rv = openPrefFile(greprefsFile);
+  rv = pref_LoadPrefsInDir(defaultPrefDir, nsnull, 0);
   if (NS_FAILED(rv)) {
     NS_WARNING("Error parsing GRE default preferences. Is this an old-style embedding app?");
   }
diff --git a/netwerk/base/public/Makefile.in b/netwerk/base/public/Makefile.in
index 2d6b8179c54d..61e88b8e49b0 100644
--- a/netwerk/base/public/Makefile.in
+++ b/netwerk/base/public/Makefile.in
@@ -146,6 +146,8 @@ EXPORTS		= \
 		nsASocketHandler.h \
 		$(NULL)
 
+PREF_JS_EXPORTS = $(srcdir)/security-prefs.js
+
 include $(topsrcdir)/config/rules.mk
 
 DEFINES += -DIMPL_NS_NET
diff --git a/xpinstall/public/Makefile.in b/xpinstall/public/Makefile.in
index 0642763ac5bf..dcc1763e7cd7 100644
--- a/xpinstall/public/Makefile.in
+++ b/xpinstall/public/Makefile.in
@@ -62,4 +62,6 @@ EXPORTS		= \
 		nsSoftwareUpdateIIDs.h \
 		$(NULL)
 
+PREF_JS_EXPORTS	= $(srcdir)/xpinstall.js
+
 include $(topsrcdir)/config/rules.mk