JExpress created a or When I try to unzip either of these files with an unzip program, I get 0k files.

You are using an unzip product which doesn't properly understand Java zip files. You need to upgrade the unzip program you're using. The latest version of both WinZip and ZipFolders now understand Java zip files.
Applies to
Version 1.0.x
zip files, winzip

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