I exceeded the specs for Trine, and when you open ( and are committed to the purchase) It gets into all the PhysX requirements. And it gave me fits!
See what happens when you get the new video card.
Usually PhysX can work in software without needing a separate PhysX card and all you have to do is install PhysX. But you may need at least a medium capability video card for it to work.
***This site*** is about a different game, but I wonder if it could be related to your Vista error. One of the posters says:
It sounds to me like there may be a window that's hidden somewhere that's actually waiting for your response to continue installation. I've dealt with games that asked me to continue, but I had to shift some menus and click around until I actually found the box. The flickering black box you mentioned leads me to believe that this may be the case. I'm not quite sure what to do, though. You could try pressing Alt+Tab. Also, you could try opening the task manager, right clicking on the installation program, and selecting either "Switch to" or "bring to front."
I wonder if there could be a window that isn't showing up because Vista is suppressing it.