I figured it out. whenever your harddrive on the computer gets full, imovie, iphoto, stop working correctly. this is why I could move pitctures but not movies, as the pics were smaller and took up less room. I have an external HDD, I moved the project and the events to that, and wella everything worked. If you open file, you can see the list of things and where they are, and it also listed the external HDD, so I just moved it there, it took some time (40 min for 25 min of video) but at least I can work again!! this cleared up my other problem about grey thumbnails as well.