You should be more specific about the To and the From of your attempted copying here.
1.) Are audio CDs involved? Data CDs? Multi-Session CDs? (CD-Extra counts as multi-session)
Trying to 'copy' a CD you've never actually ripped with PlexTools before? (could be copy-protected) Tried copying dramatically different CDs?
2.) Trying to go from same drive to same drive? If not, then what is your other CD or DVD drive? Trying to burn on-the-fly (straight from one optical drive to another) by any chance?
3.) Trying to manually go from drive to image, then back to drive? Trying to go from non-image files to drive, or what?
4.) Have you successfully done any non-'copying' burn with PlexTools on your Premium2? Have you tried burning with any software other than PlexTools?
5.) Have you tried changing the speed at which you attempt to burn? Tried any of the slower speeds like 2x or 4x, or are you only failing at the higher/max speeds?
There are so many possible factors involved, other than a defective/dying Premium2. I would be more inclined to blame Windows (especially XP SP3 or Vista) or your motherboard - rather than your Premium2 itself.