I do not know how to fix the problem but I have come up with a way to unfreeze my screen.

When it freezes, I hit the 'X' to close Poser7.  Then it asked me if I want to 'save' or not, I hit 'Cancel'.  Viola.  Screen unfrozen, back to posing.  If I get the 'End Program' prompt, I hit 'No.'

I don't get too many freezes.  When I do it is generally after a render when I am trying to return to posing mode (whatever its called).  Works every time.  But I still save frequently, just to be sure.