Eldon,
It sounds to me like your Drive has began to die for Karaoke. This is due to the hardware, that this problem is occuring. What you can try is to clean the dust out of the drive by using a can of compressed air, and blowing it in the drive with the CD Tray open.
If this still doesn't work, you can try upgrading the firmware for the drive from:
http://www.plextor.com/english/suppo...oads.html#firm
If you still have the problem, the drive will need to be replaced.