Bill, Thanks for your response. I know 0xfffffff is not NULL, but I'm wondering why the stupid variable wasn't initialized to NULL to satisfy the ASSERTION condition. I believe that you are correct in saying that one of the XP dlls got changed by the service pack, but I fail to see why Microsoft did not say anything about it in their report of the fixes. Anyway, if someone else comes up with this problem I'll look into again, I uninstalled then reinstalled Microsoft Visual C++ Standard Edition to start from square one, didn't take too long and everything is back to normal now, so I'm in business. But I definitely want to know what the heck happened... Thanks for your help! Sincerely, Alexander Wiseman Est melior esse quam videri It is better to be than to seem