CD-ROM won't mount, I/O error dev sr0 sector

Some CD's I have burnt myself do not mount in Sabayon Linux. dmesg shows the following errors:

end_request: I/O error, dev sr0, sector nnnnnnn

Buffer I/O error on device sr0, logical block nnnnnnn

 Specifying the type (iso9660) and uid & gid allows the CD's to mount:

sudo mount -t iso9660 /dev/sr0 /media/cd -o uid=`id -u`,gid=`id -g`

Not sure if this is a result of the media (Imation) or Linux/Windows burning - suspect it is the Gnome Disk Utility - Disk Image Writer.