My guess would have to be memory related also, especially if your HDD is also short on space because Windows will try to use virtual memory if your physical RAM gets filled. Try using lower resolution figures and see if you can create a bigger scene. Open the task manager (right click on the taskbar and select task manager, then the performance tab). Run Poser and add things to your scene, and watch what happens to the Available Physical Memory figure, also the Page File Usage History graph.