think of a gzip file as a compressed file, think of tar as a zip file, winzip doesn't like it when the two are used together and tends to die...
Go snag WinRar from www.rarsoft.com and untar the file (unzip). As your server is most likely on a unix/linux machine it can tar and it can global zip, but it can't just zip (unless you play with it to do so).
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