iMovie '09 - Video flickers after export.

Good afternoon.

I have spent numerous hours creating and editing a movie in iMovie 09. I exported the movie to QuickTime and when I viewed it an undesired flickering effect is occuring in the video. This does not happen where photos are inserted, only in parts that have video. I attempted to export the movie in all the different formats, but the same flickering occurs. When I view the movie in the editing pane, there is no problem.

I am confused and frustrated. Does anyone know of a way to trouble shoot this? Thanks.