I am running it on Win7 Ultimate 64-bit.
I also had some trouble getting it to run initially and don't know for sure why it started working. There was a patch released from MS about 4 weeks ago that had to do with some kind of generic application compatibility. I was in the middle of learning how to install/run XP compatibility mode when I suspect that this patch fixed the problem for me. Do you have all your updates for the OS? I can add some specifics when I get home tonight.
Turns out mine is called Risen. Sorry to bother. You're original post sounded like my complications with this game.