I had EXACTLY that same problem and pz3's I'd had open the day before either wouldn't open or crashed it all - I'm on a Powerbook 550 with 512 RAM , OS 10.2.3 running Poser in classic. What I finally did that made it install properly for me was ...... 1) drag everything out of runtime that didn't install with either P4 or ProPack and all saved pz3's worth keeping..... 2) trash the current installations of both and set extensions to Everything OFF . ,,,, 3) Re install P4, PP and that service release one right after the other and then reset extensions to whatever they normally are and Restart. Drag the saved runtime and pz3's back in & start up poser and try a test render. It worked for me after I tried about 4 other combinations of installing. Even setting extensions to Base didn't work . A TOTAL PAIN!! Hope this helps if you aren't already sorted out. At least you don't know where I live if you make a mess : ) just kidding

" Try and be nice to people, avoid eating fat, read a good book every now and then, get some walking in, and try and live together in peace and harmony with people of all creeds and nations."
-Monty Python