Apparently something was wrong with downloading some files from the download page, as they were compressed (again) by the web server, which is a waste of time and effort (as I'm talking here about the compressed files) and looked like it was responsible for corrupt downloads in some cases. That should have been fixed now. Sorry for any inconvenience.
"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning."