In playback my camcorder stops and 31:11 flashes. Any ideas?

This most likely means the taps is jammed.
You can try and get the tape to eject. To do this, remove your battery from the back of the camera. Also if your camera has another small battery under the LCD (the size if a nickel) remove it too. Wait 2 minutes. Then, plug the camera in with the power cord. Try changing the camera from playback to record mode. The tape should eject at this point. If this doesn't work, try it again but this time start in record mode and change to playback after plugging it in.
I hope this helps.