Hi, sorry I was confused. growisofs just told me that this drive(the BenQ 822A) has a ":-( /dev/cdrom: unsupported MMC profile 0" and died.dvdrecord made the mess with my media :-(
Everything indicates poor media support by your unit. Try different media brand, preferably explicitly recommended by vendor. If even brand-name media doesn't work, unit is most likely broken. Ask your vendor to replace it. A.