1. Put a cdrw into burner
2. Cancel automatic ask if burn something because of inserted a blank medium.
3. Click "burn with xfce" in context menu of an iso file.
4. Wait for completion of burn process.
5. System freezes after burn completed.
It seems that it has something to do with the automount feature that locks the tray and then system freezes because of a deadlock maybe, trying infinitely to open the tray.
I deactivated automatic mount of new hotplug devices.
EDIT: I do not think that the burner is broken cause the product is okay and usable after a hard system reset.
EDIT: cdrecord works directly from terminal. So I guess I am right with some problem with X applications or HAL or something like that...

raphael[~]$ hdparm -i /dev/hda
bash: hdparm: command not found
raphael[~]$ /sbin/hdparm -i /dev/hda
/dev/hda:
Model=BENQ DVD LS DW1655, FwRev=BCDB, SerialNo=KWG1601319SC0
Config={ Fixed Removeable DTR<=5Mbs DTR>10Mbs nonMagnetic }
RawCHS=0/0/0, TrkSize=0, SectSize=0, ECCbytes=0
BuffType=unknown, BuffSize=0kB, MaxMultSect=0
(maybe): CurCHS=0/0/0, CurSects=0, LBA=yes, LBAsects=0
IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
PIO modes: pio0 pio1 pio2 pio3 pio4
DMA modes: mdma0 mdma1 mdma2
UDMA modes: udma0 udma1 *udma2
AdvancedPM=no
Drive conforms to: Unspecified: ATA/ATAPI-3,6
* signifies the current active mode
raphael[~]$ /sbin/hdparm -i /dev/hdb
/dev/hdb:
Model=LTN403L, FwRev=FL1E, SerialNo=
Config={ SpinMotCtl Removeable DTR<=5Mbs DTR>10Mbs nonMagnetic }
RawCHS=0/0/0, TrkSize=0, SectSize=0, ECCbytes=0
BuffType=unknown, BuffSize=0kB, MaxMultSect=0
(maybe): CurCHS=0/0/0, CurSects=0, LBA=yes, LBAsects=0
IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
PIO modes: pio0 pio1 pio2 pio3 pio4
DMA modes: sdma0 sdma1 sdma2 mdma0 mdma1 mdma2
UDMA modes: udma0 udma1 *udma2
AdvancedPM=no
* signifies the current active mode
raphael[~]$ ls -l /dev/cd*
lrwxrwxrwx 1 root root 3 2010-01-22 18:53 /dev/cdr -> hda
lrwxrwxrwx 1 root root 3 2010-01-22 18:53 /dev/cdr1 -> hda
lrwxrwxrwx 1 root root 3 2010-01-22 18:53 /dev/cdrom -> hda
lrwxrwxrwx 1 root root 3 2010-01-22 18:53 /dev/cdrom0 -> hdb
lrwxrwxrwx 1 root root 3 2010-01-22 18:53 /dev/cdrom1 -> hda
lrwxrwxrwx 1 root root 3 2010-01-22 18:53 /dev/cdrw -> hda
lrwxrwxrwx 1 root root 3 2010-01-22 18:53 /dev/cdrw1 -> hda
lrwxrwxrwx 1 root root 3 2010-01-22 18:53 /dev/cdwriter -> hda
lrwxrwxrwx 1 root root 3 2010-01-22 18:53 /dev/cdwriter1 -> hda