Thank you Bagginsbill and Tyger_purr.

I just reported my memory leak problem to Smith Micro. Even if I load a blank scene and do nothing, memory consumption of the Poser.exe process increases by 30KB/sec. I usually leaave my PC alone during rendering (watching TV). So, when you get back after 30min or so and move the mouse, the "out of memory" error appears, because Poser allocated a lot of memory even if it's in idle mode after rendering.

With my previous Poser version, memory consumption stays constant when I do nothing (as expected).

EDIT: Just to give you some idea. During the time it took to report the problem and write this forum post, Poser memory consumption increased from 17MB to 73MB. When I minimize Poser, memory drops again to 17MB and starts increasing slowly but steady...