Thanks.
I am using Redhat 8.0 with the latest versions of apache mysql and php. I can upload zip files fine via ftp but through submitting in http post it causes probs.
Have you tried posting your problem to Linux, Unix, and *nix like Operating Systems [webmasterworld.com]? Maybe they could help you since your problem seems to be more akin to an OS related problem than anything else.
I wish I could help more, but I know next to nothing about Redhat.
Pendanticist.
I haven't had this problem and am not too sure what is going on. I would try some searches at <your favorite SE> to see what comes up.
One thing to possibly investigate would be whether your server is running mod_gzip as part of Apache, an HTTP Compression Module designed to save bandwidth by compressing files before they are sent to the browser for display. I would be a little surprised, but it's at least conceivable that gzip is trying (and obviously failing) to uncompress the zip file?