And it occurs in Poser 8, like, when you said, indirect lighting is involvled in the render. I have the same problem from time to time. I even had a render where the problem occured in two different places when I changed the render size.

I don't have an answer for how to correct it (except not using indirect lighting?). I just wanted you to know that it is not specific to your machine...

If I had a nickle for ever time a woman told me to get lost, I could buy Manhattan.