I'm sorry that people are having troubles but as I said there's nothing I can do without knowing what kind of systems you have.
As long as everyone keeps posting in this thread that they're having issues and they don't provide any info beyond that, all I can suggest is to try downloading it again and turn off your virus checker. Without knowing which virus checker you're using I can't even tell you how to do that. Google will be of help there I imagine.. That's about the only advice I can give with the info I've got.
I have no idea how common this problem is, and it only seems to be happening over the last couple of weeks, so it could just be bad internet connections. Like I say I'm looking for places to mirror the file so hopefully that will cut down on the problem. I also uploaded a newer build to see if that helped but apparently not. Hopefully it will be figured out soon.