First you'll need to configure k3b. Here is a post about it. Secondly if you've done the k3b setup your /etc/fstab file is probably hosed. If you could post it please. Also post the output of cdrecord -scanbus. Since you have a cdburner in your system Linux is using SCSI emulation to access your drives. Therefor they will be listed on the SCSI bus. Try this:

ls -al /dev/cdrom It should be a symbolic link to one of your drives. If it is a symlink to the wrong drive then it's not going to work. Post some details and we can go from there.