I'm trying to import a video into Photoshop to make it a .gif file, but when I try to import the video, an error box pops up:

"Could not complete your request because it is not the right kind of document."

What does this mean? How can I fix it? Thanks.

I have also tried in ImageReady, it comes up with the same error.
I have tried these file types: .MOV, .AVI.