I have Poser 6, 7 and 8 plus Vue 8 and 8.5 all running on Windows 7 Ultimate 64 without any problems..
As Rich says, it maybe an admin thing, or maybe it's because you're running W7 on a MAC, I don't know enough about MAC's to say, sorry..

Injustice will be avenged.
Cofiwch Dryweryn.