I cannot repeat this in either of of My P5 installs, and it's driving me nuts! Can you do a search in your Poser installation for shadow.tmp files and see if you have any that might be left over? Sr2 and earlier (and Sr3 with animations) tended to leave the files in place, and they interfere with the shadow map function in Sr4.

thou and I, my friend, can, in the most flunkey world, make, each of us, one non-flunkey, one hero, if we like: that will be two heroes to begin with. (Carlyle)