Yeah, Firefly has looked to hav epotential for a while now :) Hmmm...it might be interesting (though not terribly useful) to cut out the reflective materials, or perhaps reduce the number of "bounces" light can be traced along, and see how that affects stability (whether you can render more frames or not). However since either would be prone to affecting the quality of the render, you might not feel inclined towards doing this. It becomes steadily more apparent that Poser has some serious memory leak/s in it somewhere :(