2005 VW Jetta CD fault: CDC Hardware Error?

This radio displays the fault, "CDC Hardware Error" when radio is on. The radio plays in AM or FM but about every three minutes emits a single tone and the radio displays the error message for about four seconds and the radio stops while the error message is displayed. The radio returns after the error message goes away. The CD mode is inoperative and I was told that a CD disc was stuck in the unit. I don't know for sure.
Does anyone know what the problem is and what to do to repair it?
I don't know the radio make or model since I did not get an owners manual with the car.

Thanks for your help,
John