I was getting a little suspicious with the corrupted zip file because each time I would try to repair it and each time only one file, the same file each time, would be saved. Now I assumed the ZIP file was corrupted because the windows XP's extractor said it was, and so did the latest version of WinRAR, but turns out that it is a WinZip 9.0 encoded thing and requires WinZip 9.0. It extracted fine once I tried using that. If you go to the Download Page there is a note there telling you that it requires WinZip 9.0, but I didn't see it.
The ZIP file is the same size as the extracted files. They have only zipped it into an archive because there are multiple install files and they probably wanted to keep them all together instead of making people download multiple files. The only problem I have with this is that it requires WinZip 9.0.