Ya, I notice similar problems when trying to read a defective disc.
Only solution = power down, power back up.
You could try using this - http://www.majorgeeks.com/download2623.html
Or you could sand the bottom of the disc with white toothpaste and your thumb, going from center to outer edge. If you remove enough of the damage this way, this disc could then be read well. Make an .iso of it if possible, then throw out the original