Aperture 3, Apple's pro photo application, has had a bumpy start since its release in February 2010. Unfortunately, one of the early casualties was iMovie '09, which could crash when building thumbnails of movie files in Aperture's library. iMovie 8.0.6 [1] fixes the problem. (Free update, 35.84 MB)
[1]: http://support.apple.com/kb/DL859