I hate to be the one in the thread who says "spend money"  but I can't recommend the new carrara 3d express enough for rendering.  Rendering in Poser is a nightmare.  I got it for $20.00.  Don't feel like it's all you.  ALOT of it is the program being a pain in the butt!  

Wish I could help more, but I can sympathize and tell you that at one point I was exactly where you are (especially rendering in different parts) and C3de solved all those problems for me.

I am:  aka Velocity3d