Thanks to everyone for your input. I decreased the bucket size to 8, and the result was the same -- approximately 20 images were rendered before Poser hung. The scene has 4 lights and has some reflections as shown in the attached image, but shadows are turned off.

I'm running Win2K SP3 with all of the most recent patches. If anyone has any more ideas, please post them. My next idea is to see if I have the same problem when I build a new system.