Here's an example of what was happening to me:
I don't know if the problem I had was the same thing you're dealing with, but I spent a good chunk of my afternoon doing a computer take-over as well, and while the dude didn't seem to completely know what was going on, his best guess was to repair my computer's permissions in Disk Utility. After we did that, I had some initial problems, so I didn't think it was fixed. But after that day, I haven't had a single problem with Premiere yet. That was about a week ago. Apparently I had some big issues with my computer's permissions that Adobe kept clashing with or something. He also suggested I get one of the nvidia cards that Adobe recommends, which I'll probably do when I'm not as poor.
I hope that helps.
2010 MBP i5 8GB RAM
