Okay...
I figured out the problem
PM hangs up when it encounters a file type it does recognize. The culprit looks to be the .mpg extension. Once it scans a folder with a mpg file in it, it freezes. To see what I mean stick a meg file in any folder with jpeg files. The thumbnails will not display or a couple will before the program crashes.
I tried uninstalling QuickTime on my development system and then browsing a folder with various file types, including MPG, MP4, MOV, AVI, and JPEGs and had no problems at all. The previously rendered images showed up with proxy images now that QT was missing but no hangs, crashes, etc.
Any ideas on getting me able to reproduce this issue on my end?
Thanks,
-Kirk