Aperture Crashing Regularly

I figured it was normal for a complex program to crash once in a while, but this is ridiculous. Aperture has worked fine most of the time for the last year and a half.

Last night I imported pics from my 60D to my 2009 MBP with Lion. After importing, while processing, Aperture "quit unexpectedly". I checked software updated and Mac said there were no more updates available. It continued to quit every time I opened it. I repaired the library twice, no help. I repaired permissions, no help. I rebuilt the library, and it was fine...until I imported the shots again from Photomatix, same story again.

After rebuilding again, it was fine last night. I was thinking I had to now rebuild after each import. Then today I wanted to show some pics, and it quit immediately again each time I opened it. After rebuilding in the middle of the meeting, it was fine for the rest of the meeting. I have yet to try it tonight.

Any ideas would be greatly appreciated.
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Ed Rizk