mount DVD - invalid argument

[Max Russell]

I have two DVD drives on my machine.

max@~: grep acd /var/run/dmesg.boot
acd0: DVDR <PIONEER DVD-RW DVR-111D/1.19> at ata1-master UDMA66
acd1: DMA limited to UDMA33, device found non-ATA66 cable
acd1: DVDROM <ASUS DVD-E616A2/1.03> at ata1-slave UDMA33

the optical section of my fstab is like this:

/dev/acd0 /cdrom cd9660 ro,noauto 0 0
/dev/acd1 /cdrom cd9660 ro,noauto 0 0

however, when I try and mount a DVD, I get the following:

max@~: sudo mount_cd9660 -s 0 /dev/acd0 /cdrom
mount_cd9660: /dev/acd0: Invalid argument

I have been able to mount CDs.

If I'm missing something really obvious, any help would be appreciated.

ta

Max