1. Did you try converting another file, to see if that worked?
2. CovertXtoDVD is about to go to v5xxx, so you are way behind.
3. Is your computer old? A lot of older computers are struggling with some of the newer video files we've been seeing here.
Convert X said immediately after I loaded the file that is was an unrecognized format
I'd say that's where the problem lies. There's probably something wrong with the video file itself. I've gotten a few "stinkers" over the years and I've made a special folder for the one I think are worth keeping.