I have used ProAnimator on and off for a few years. Currently running 5.0.5 on AE CS5 on a Mac Pro (10.6.8) with 8 cores, 16gb ram. I don't think it's the newest version of ProAnimator but upgrading in the middle of a project with deadlines has the potential for sleepless nights. :) Either way, I have had this problem over years on other computers as well.
Anyways, I almost always have illustrator based objects in my scenes and almost always use the Comp Camera from AE for my animations and it seems that ProAnimator doesn't stay stable for very long. It becomes a game of chance when going into ProAnimator to change anything. In AE, ProAnimator renders well but if I go into ProAnimator itself, theres about a 40% chance it will crash on launch. Once in, it crashes less often but still happens regularly enough to be bothersome.
Is there something I'm doing wrong? Any way to increase the stability? The projects are not very complex or detailed in models, materials or animation. In my current project I have about a dozen illustrator objects, each on its own animation track with some ProAnimator text and a simple animation. I also have the shadow map resolution increased for nicer shadows in close-up camera views of the 3d objects. The camera flys around with additional elements in AE.
Be sure to download ProAnimator version 5.0.9. It contains numerous bug fixes, so even though you may be hesitant about upgrading during a project, 5.0.8 and 5.0.9 are all about crash fixes, stability, and optimization. So if you are not using the latest version, you may be prone to many other crashes.
Hope this helps. If you're still having issues with version 5.0.9, please let me know.