White layers when loading .avi clip in CS3 Extended

I'm trying to make an animation gif using a video clip. I have it shortened to what I want using Windows Movie Maker and converted it using a program from .wmv to .avi since avi is supposed to be supported by CS3 Extended. I go File > Import > Video Frames to Layers > pick .avi > load > From beginning to end/make frame animation > ok. I just get a lot of blank layers. What am I doing wrong?