For the time being, I'll be uploading samples in RAR format instead of ZIP.
The reason for this is that for some reason, I'm unable to consistently upload valid ZIP files to Community Server. I've tested the files locally and sent them over GTalk to other people who could open them with no problem. When I upload them to Community Server, they get changed. (I've tried this literally 40-50 times) Sometimes it works after the 5th or 6th try, sometimes not at all. It's incredibly frustrating.
Basically what happens is the root folder of the ZIP archive appears to be losing its information. If you extract it and add a ZIP extension, everything opens fine. That's not really an elegant workaround though.
The odd thing is, RAR files don't exhibit this problem. So, for now, I'm taking that option.