Greetings, potential convert!
It sounds like you might have a corrupted media clip somewhere in
your sequence that is refusing to be cut by the 'extract' command.
Is all of the media linked in your Premiere project?
I finally moved to the end of the timeline and extracted, and it worked, kept moving my way back in the timeline, and when I got to about hallf-hour (one hour in/half our left on timeline), it crashed again.
You can possibly use this method to zero in and isolate the clip that is causing the crash.
All clips appear to be online. Isolated a section after a dozen more crashes, but couldn't see anything wrong with the media. Went to a different timeline, made a cut, and yet another crash. Not a promising start.
Is the system generally "crashy" with large projects; I had read on a doc forum that projects over a half-hour were a problem. I'm beginning to agree. Even if it is corrupted media, I never encountered crashes for this reason with fcp (it would crash for other reasons, but that's a different story...), whether clips were offline or corrupted, I could still cut.