Have you tried multiple discs? If you have try cleaning one very good. I know what you are saying, they are clean. I have had this happen with new discs on brand new machines. Get a t-shirt and lightly mist the disc with water, wipe from the center hole out until it is clean and dry, tilt it sideways in a light and see that there are no streaks or prints. If this does not work the problem may be the unit.

The laser head needs to be cleaned up or to replace