I can think of 2 things.

1. nVidia card with old drivers
2. Some sort of problem with the temporary files, the OS is not letting Poserpro save the temp files necessary for the undo operation.
   BTW, have you set up Poser to render as a separate thread, and the number of processes to 4? Also, to get the 64bit render engine going, you need to render to background or to the queue (doesn't have to render to a network, you can use the network queue on a single machine too).

still hooked to real life and enjoying the siesta!
Visit my blog! :D
Visit my portfolio! :D