mount: /dev/sr0 is not a valid block device

[Wim Vriend]

Hello,
Having a problem with my USB cdwriter
mount: /dev/sr0 is not a valid block device
I have tried "pmount /dev/sr0" as user and root

wim at ubuntu ~ $ pmount /dev/sr0
mount: /dev/sr0 is not a valid block device
wim at ubuntu ~ $

I have changed the line "/dev/scd0" to "/dev/sr0" in /etc/fstab
I have put "sg" in /etc/modules

Can anybody tell me how to solve this problem

TIA
Wim