I had that and other things go wrong in Poser 7 a while back.  Sometimes exiting and restarting the program was enough and sometimes it required restarting the computer.  Never knew what caused it.

It also happened sometimes if I was tyring to paint part of an object (prop or figure) that was already painted once or twice, such as a detail on a logo on a shirt.  Spawning the props was not a constant trigger, nor was changing camera angles.  I just thought I somehow overworked the program. :p