Jeff is correct. There is a chance that the lens is dirty, thus preventing the laser from being able to read the disc. The lens may be cleaned during the DVD Drive hub/spindle cleaning described in this thread:
Be sure to position the roller/slider to the far left postion at the rear of the disc tray before securing the drive lid.
If the lens and hub/spindle cleaning does not correct the problem then the Panasonic $130 flat-rate repair is your best option for this outstanding full-featured combo recorder. I suggest calling the Elgin Illinois Service Center first. They may refer you to the Elk Grove Village Illinois Service Center. Current information is found here: