I've had this problem for a while, but never really cared, because I didn't use the Themes. Now, I need to use them and remembered, they don't work. I've tried everything! Nothing fixes it! It goes down to the little clip viewer thing and has an empty red bar, but it doesn't start rendering! I've completely trashed iMovie and all its files and reinstalled it and it still doesn't fix it! I'm running Mac OS 10.4.11, Tiger. Can someone please help me?