Have you installed Poser 7 to the C:Program Files (x86) folder?

I'm running Poser 7 fine on both Windows 7 Pro 32-bit AND Windows 7 Ultimate 64 bit.  I have no problems at all with Poser 7 installed on the root directory: C:Poser 7.

Windows 7 (and VISTA) don't care much for having programs write to the protected area of the disc.  I installed Poser to the root directory and maintain external Runtimes in the 'My Documents" folders.

Best Wishes,
Rªnce