What's the exact error message?
When you see that message, what options are you given? Can you "Continue"?
This is why I never open and edit files from a Zip program without saving the file to some other location first, then re-zipping.
I have an Excel file I opened through winzip, edited and saved. When I tried to open it again through the winzip file, it said something about being overridden by the archived file. Is there a way I can get back to the one with all my new, edited information on it?