The Plextor 8 20 is a pretty good unit except it doesn't support write simulation. That's not important though.

You must have at least Firmware 1.07 and the unit has to be manufactured after March 1999 that was shipped with 1.03 or later.

Go to the following site for a pretty good FAQ on CloneCD:

http://www.cdrinfo.com/software/clonecd/page2.shtml