Hitachi DZ-MV730A DVD Camcorder "player stopped mid" Questions

...mid-playback on the camcorder, it stops playing and freezes up. I can do nothing at this point. It won't even turn off. The only fix is to remove the battery and then start again. However, after ...

stopped recording and gave the message "bad disc". When she ejected the disc and re-inserted she got the same message. When we attempted to play back the disc on 3 different dvd players and a computer