iMovie won't upload/recognize certain iphone videos from iPhoto.

I have a MacBook, Mac OS X version 10.6.8. I have recently started making some more movies to document my daughter's life in iMovie. I am having trouble getting certain movies from iPhoto to transfer to iMovie. When I opened iMovie it said it was making thumbnails, and it did...but not for all of the movies from my iPhone. I didn't realize this until I was almost done with my movie in iMovie. I restarted both iMovie and iPhoto to try to get the movies recognized. I have tried so many different things and nothing is working. All movies are .mov form. I am using the '08 version of both iMovie and iPhoto. Now I can't drag the movies anywhere, they are grey when I look them up in Finder. Any ideas?

Here is a screenshot from one of my attempts to make it work.