Try reinstalling Plextools: Select Preferences, select general tab, untag save settings upon exit, exit Plextools, restart Plextools, to back to general preferences tab, clear registry settings, quit plextools, uninstall plextools, reboot, install plextools.
Alternatively check what ASPI layer you are using (Windows, Adaptec, Nero?). Are you using any chipset specific IDE drivers?
That is a MEDIA error code. I sometimes get these when I try to do a B/J scan on a US-CDRW. See below.
Since it is a media error i doubt it's the drives hardware. In my case the above mentioned error with an US-CDRW occured imediately on a 716a while my 712a would at least start the test and give an error at position 5min or so. I very much doubt that both my drives are broken. I've meanwhile used that same CDRW again and the B/J scan is now working right away in the 716a. I guess that getting that error means the burn was probably not very good. How does a C1/2/U scan look like? You might eventually want try another brand of media.