You might also want to check into what the maximum size file is for that program. Some file types have maximums. You can create a file larger and it will seem like it works, but when you try to use that file it will show as corrupt.
This is most likely your problem. Compression utilities and those that create uncompressed archives are notorious for creating archives outside of their limit threasholds. Call or e-mail their support team and ask about the archive limits. This may be broken out into several catagories, including directory structure, total archive size, number of files within an archive, etc., etc..

--TH13