The pz3 issue is something to do with the lights...

If I load a P6 pz3 it loads with ultra bright lights and I end up with a... light 1... LIGHT 1... light 2... LIGHT 2, etc in the scene... with duplicate lights..

Sooo... I just fired up P7 again... deleted all it's lights... loaded a P6 pz3 and... it has all sorts of lights listed, but only 1 bright one appears in the scene... the others aren't just blacked out... they are not there.

As soon as I try to alter the one light that is in the scene... kapoooie... P7 vanishes...

"You don't have to be mad to use Poser... but it helps"