mplayer not detecting dvd

[norman]

I am trying to get mplayer to play dvd.When i try to play a dvd i the 
error "failed to open dvd://1.

here is my fstab 
         proc            /proc           proc    defaults        0       0
# /dev/sda5
UUID=962fb933-282f-4b90-a04a-7c4fe4326d99 /               ext3    
defaults,errors=remount-ro 0       1
# /dev/sda6
UUID=d6544670-88f6-44e9-96f8-8fd0f14d2e8b none            swap    
sw              0       0
/dev/scd0       /media/cdrom0   udf,iso9660 user,noauto     0       0

I change the setting mplayer  perference-misc-dvd device to /dev/scd0 
then /media/cdrom0,still wont work any idea.