The videos are there, but I just get the hourglass picture. If I doubleclick them, they'll play just fine. But I have no way of quickly scanning thumbnails to pick a movie.
While we're on the subject of thumbnails, I can only see thumbnails for my pictures if I make them larger. If I try to make the thumbnails smaller, they just won't ever show up. I have about 1800 video clips (very few longer than 1 minute), and about 10,000 pictures.