I didn't have any problems when using PP files in Poser 5. I didn't use Poser 4 files because everytime I tried I was sent on a hunt to find files. I've only been using Poser 6 for a short time, but so far other than premade light sets, I haven't had any problems. Premade light sets however are pretty much useless in Poser 6 if they have more than 8 lights because of this OpenGL stuff. If there are more than 8 lights the image in the pose room turns black and you can't see to do anything. It renders ok though, but not being able to see the pose room image after applying the lights is a real problem, and not all computers can handle this OpenGL stuff... mine totally seizes up.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi