Definitely a Windows issue!
I'm assuming the problem stems from your Poser runtimes being located in your Program Files directory. I ran into the same problem; I moved all of my runtimes (except for the default) to My Documents and everything was fine after. The problem I ran into was that stuff that was saved within Poser before the move was still invisible. You can still get at the content; I believe if you Google "Virtual Store" you'll find the answer.