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Most of times this is due to a bad burned media, and most of time this is due to a low quality disc.
Another possibility is that you burned a file that your standalone is not able to play (for example an AVI movie: not all standalones are able to play these files).
What discs are you using? At what speed did you burn? What burner do you have? What is exactly the file you burned on the disc (avi or vob)?