I’m seeing a lot of this same issue. When working in the program, even if I’m not touching the program at all, it will eventually crash after around 5 minutes. Every thread has the same symptoms, every person has a completely different PC. I have a fairly typical gaming PC, running at 2gb of ram with a geforce 8600 and intel core2 duo e4400. If it doesn’t run properly on a very typical set of hardware like mine, then that leads me to believe there’s an issue with the software.
it looks like video card is not your issue since you have 8600.
One thing I can tell is that if you are using Vista, go to preferences>OpenGL tab and check if ‘support triple buffering’ is checked. If not, check it and restart Animate to apply changes. If it is checked, try uncheck it and restart Animate.