On my Plex Premium and 712a, i also get read errors on "copy controlled" audio cd's, this is all the cd's state, the actual protection used is not mentioned anywhere.
An example would be Michelle Branch's Hotel Paper :o UK version, the cd is very easy to copy using clonecd or alcohol 120%, its just during audio extraction it produces lots of errors. Though when plex tools finished extracting, i couldnt find anything wrong with the wav files, they all sounded ok. The protection on this disk asked for files to be installed to play the cd on a pc, unsurprisingly i refused
The other cd i have is a Pet Shop Boys one which is exactly the same as above. The long way round is to copy the cd using clone/alcohol, you could try eac, and use "1st session" and then rip the copied disk, and guess what, theres no errors when extracting.
Further info is here on that disk and others: http://ukcdr.org/issues/cd/bad/