I did that to increase the simulation resolution so collisions would work better. It's a pretty standard practice, from what I've seen. Increase sim speed by 5x, more frames are processed each second, collisions don't get missed as often. A lot of scenes I've downloaded do the exact same thing (especially engines and other more complex machines).
It's never caused any problems for me (or any of the other 130+ people who downloaded it, apparently), and I do, in fact, use Windows. But, just in case, I'll change the keys and re-upload.
furiousman: Actually, I think I read somewhere that someone is going to be still working on Phun, so we may see some more updates yet.. maybe not as much as for Algodoo, but still....
chronos: Not quite the same thing.. unless there's some subtle sarcasm in your scene that I'm not getting