I'm also having a problem with Poser 7 closing unexpectedly (it just vanishes) after a render is done and when I delete lights from a scene.  This occurs with both my desktop and laptop with SR 1 installed. However, I don't have any issues with Poser 7 SR1 on my secondary desktop with Vista. 

I also tried an ATi Radeon 1600 Pro instead of the Nvidia GS in my Primary desktop config but the problem didn't go away.

My Primary Desktop Config:
Windows XP Media Center Edition
AMD Athlon 64 3800
2GB RAM
Nvidia 7600 GS

My Secondary Desktop Config:
Windows Vista Home Premium
AMD Athlon 65 X2 5000
2GB RAM
Nvidia 7600 GS

My Laptop:
Windows XP Professional
AMD Turion X2
1GB RAM
ATi Integrated graphics acceleration

I don't think its an ATi driver issue since it happens with my NVIDIA cards also. This issue is very annoying indeed.......