It's a Poser's error, nothing to do with memory.

• Go to the frame that crashes and save the scene (pz3).
• Quit Poser and open it again loading this pz3, render only this frame and see if crashes.
• Proably it will crash, if not ignore the following and it is another story.
• If crashed, remove some element from the scene, save as another pz3, render this frame and see if crahes.
• Repeat the process until stops crashing or is nothing left in the scene.
• If stopped crashing add again elements or load a previous pz3 and remove other element.
• Repeat until you identify the element that is the cause of the crash, probably will crash with only this demoniac element in the scene.
  Depending on the results maybe you can get a clue of what is happening.

Stupidity also evolves!