I've been having many issues with Poser5 locking up during a render; almost always with "Adding objects..." being displayed. My experience is that this is related to bugs in Poser5 related to the complexity of the shadow maps created to do shadowing. I do a lot of work with dynamic hair, and not surprisingly, hair strands create fairly complex shadows. I find that a large number of lights w/shadows, or large shadow map sizes, or large number of complex objects, or any combination of the above will cause Poser5 to hang. I've found that the next step after the "Adding objects..." function is the "Rendering shadowmaps..." function. I suspect it freezes on "Adding objects..." because it's trying to transition to the "Rendering shadowmaps" and can't. The solution I've used is to reduce one or more of the variables I've listed above. This has solved the problem for me.