Originally Posted by drwinn
... I am using WinZip 14.5 ... Change zipx to epub ...
I think that might be your problem - you're zipping the files using WinZip 14's default "ZipX" compression, which is relatively new and may not yet be fully supported by other utilities. I'd suggest zipping the files using the "Legacy Zip 2.0" setting instead, and see if that solves the problem.