Try playing it with VLC media player. If it plays in there then you'll know you need some codecs. If it doesn't then the file might be corrupt. Was it rated on bitzi as a good file?

Don't know if it'll be a dud or not. Some dvd players have trouble playing burnt dvd's and some are sensitive to the brand of dvd you use. You won't know for sure until you try playing it in their player.

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