I've fixed and re-rendered the titles in my project several times, and now, after I render, the credits no longer play. I've gone over the settings with a fine-tooth comb and there's nothing wrong with them that I can see. I can scroll across them and see them in the timeline until I render, at which point they go away. I've tried shutting down FCP and re-opening it, deleting the credits and starting over, putting them on another video line - nothing works. Any suggestions?