More help please!! with Nero 7

I've burned a few DVD's now no problem.

All of a sudden I'm having a problem with one movie.

I'm doing this:

Make your own DVD-video
Add Video Files (it's an .avi)
Then I hit next until I get to the screen with the burn button, and when I hit it I get this message:

Unable to prepare data for recording:Prepare session failed:Transcoding of video failed.

I never got it before and I'm doing the same thing. WTF????