i reauthored a dvd movie with dvd shrink, the lastest version, encoded it to vob's. there are 4 vob files and the first three play in my dvd software player but the 4th and last vob file doesnt play it says unsupported file. the first three files are 1,048,574 kb the last one is 387,636 kb.. whats wrong? why wont it play?

thanks