That means that the CDG's you have are most likely good.
I do not believe that this issue is software. It is most likely hardware and the Plextor Drive.
There Help site is:
http://www.plextor.com/english/suppo...lexhelper.html
Their Phone number is: 1.510.440.2000
I would Place a call to them and see what they had to say. It may save you some time.