Not offhand. The only time I have problems with the .avi files is when Poser crashes before finishing the animation. In that circumstance, Poser doesn't write the back-end of the file, and the .avi cannot be recognized by players or editors, even if it's 99.9% finished.

I've also experienced a strange problem (with both P4 and P5) where, after rendering and outputing an .avi, I cannot output another without crashing Poser thereafter. Rebooting is necessary if I want to do more. In all fairness, I suspect this is more of an issue with my installation of Video for Windows than it is a Poser bug. My media player sometimes misbehaves with files I know are fine.

But for the reasons above, I'm now reluctantly outputing all of my animations as image sequences, rather than .avi files. If and when Poser crashes due to cumulative memory leaks, I can relaunch and continue rendering the sequence from the point it prematurely ended. And I can assemble the image sequences into .avi files using VirtualDub, Animation Shop, or other utilities.