Thank goodness there are others with the same problem, I was beginning to think I was going nuts. 8P
At this time, after I've added a new piece to a scene and done a render, I close P6, empty all the temp and rubbish files, defrag my drive, sort out the registry, then restart before I add anything more.
I know it's a rediculous thing to have to do but there doesn't seem to be any other way to get it to behave.
Another problem I've found is when importing another Poser document to the one I'm working on. When I try to save the merged file that's when it tells me I must save and close, I'm running out of memory, and this is when it saves those 0kb Pz3's.
I know this is a lie because if I build up a scene the way I said above, using the exact same components, the file can be gianormous, but it will save.
Pfft!to CL. 8)

Catlin