diff --git a/xpinstall/stub/xpistub.cpp b/xpinstall/stub/xpistub.cpp
index 7a9b29039a31..294949a9c9ed 100644
--- a/xpinstall/stub/xpistub.cpp
+++ b/xpinstall/stub/xpistub.cpp
@@ -40,6 +40,10 @@
 
 #include "plstr.h"
 
+#ifdef XP_PC
+#include <direct.h>
+#endif
+
 
 
 //------------------------------------------------------------------------
@@ -75,7 +79,34 @@ PR_PUBLIC_API(nsresult) XPI_Init(
     if (!NS_SUCCEEDED(rv))
         return rv;
 
+#ifdef XP_PC
+    //
+    // Passing 0 as the 2nd parameter to AutoRegister() will tell it to
+    // automatically determine the path to the components directory.
+    // Since XPI_Init() is being called by Setup.exe, not apprunner.exe,
+    // the wrong components directory is determined.
+    // As a requirement to loading xpistub.dll, it must be loaded from
+    // the same directory as xpcom.dll.
+    // This makes is easy to locate the correct components directory by
+    // using a form of GetCurrentDirectory().
+    //
+    // Since nsFileSpec() does not contain a GetCwd() function,
+    // a call to getcwd() is being used under Windows only.
+    //
+
+    char            szTemp[_MAX_PATH];
+    getcwd(szTemp, _MAX_PATH);
+    PL_strcat(szTemp, "\\");
+    PL_strcat(szTemp, "components");
+    nsfsDirectory = szTemp;
+    rv = NS_NewFileSpecWithSpec(*(&nsfsDirectory), getter_AddRefs(nsIfsDirectory));
+    if(NS_FAILED(rv))
+      return rv;
+
+    rv = nsComponentManager::AutoRegister(nsIComponentManager::NS_Startup, nsIfsDirectory);
+#else
     rv = nsComponentManager::AutoRegister(nsIComponentManager::NS_Startup, 0);
+#endif
     if (NS_SUCCEEDED(rv))
     {
         rv = nsComponentManager::CreateInstance(kSoftwareUpdateCID,