Where id the video comer form? Have you converted it or edited it?
enjoy your magic machine
I have the same problem. It is something I purchased from ITunes, I try to tranfer. says won't play, check file, says this file is in correct format. Now what?
I am having the exact same problem.
I've found that you can get the video player app to work again by doing a search for a video that you know works properly and launching the video from there. That will at least get the app working again.
I have also found that deleting the video from your ipad and resyncing it will sometimes work - although not always (and then sometimes they just stop working if you stop watching a video and go back at a later date).
If you find a solution, btw, please post here so others can try what worked for you.
.mp4 video play in iTunes, syncs to iPad but won't play