Help! iMovie shuts down on export

iMovie keeps shutting down on me when I try to export the movie. On a side note, it also shuts down when I try to play in full screen mode, but it will let me play it after the initial shut down. The export won't work at all. I've tried all of the options.

I am using a MacbookPro version 10.7.5 w 2ghz intel i& with plenty of memory space. I ran an utility test, but it found no errors. I am trying to export a 10min 30sec video to either Quicktime or Vimeo. The movie is from my camera and the music comes from the Mac.

I've never had this problem before and I just downloaded updates yesterday.

Please help! This is for a college project!

thanks.