Ok, tried a couple of things that were causing others to crash. Savng a morph target from with in Poser, then loading and applying it back to the figure caused no crashes for me. I haven't tried it with third party morphs though. Tried deleting lights, (before and after a render) manually and with the delete lights script (which is what I usually use). No crashes. Changed rooms multiple times, no crashes.

Deleting lights and changing rooms all change the preview window. Definitely something that could be related to the graphics card. Changing Scree to OpenGL or vice versa could definitely have an impact on that bug. If the switch doesn't fix the problem then it might also be worth updating the graphics card drivers. (If you don't have experience with that, make sure to print and follow the directions on the ATI or NVidia web sites. As long as the directions are followed, it's a pretty smooth process).