My kids just finished editing a movie.  It plays back just fine.  However, when I play the saved version there are frames that freeze and look all distorted.  Please help.  I have saved it a couple of different ways, high quality, recommended, even custom settings.  The freeze frames and distortions are in different places on different saved movies.  The distortions only come after saving the movie, does anyone have a solution for this? 

Thanks for your help!!