How to Animate GIF files from video using Photoshop CS3
This tutorial shows you how to make an animated GIF out of any video on Adobe Photoshop CS3.
If you are having problems with the video not showing up, then: Does the video file work in other programs, and do any other video files work in Photoshop? You might have a codec missing or it could be a rendering problem. You just need to find the source of the problem (i.e. find out if another file will work in CS3).