I'm just going to have to guess what's wrong...
wet... dunno man. You're running as admin, right? You might try downloading directly off the zune.net website, just to make sure it's complete and everything.
wladi and theFunk... the Zune software is meant to only work on US windows based OS's. Maybe they're cracking down on that. I see it say EULA (End User License Agreement), so maybe there's something in there about what acceptable OSs there are.