but as root no problem. When logged in as normal user, check this:
ls -l /dev/sr0 brw-rw----+ 1 root disk 11, 0 2008-11-23 17:03 /dev/sr0
If there is no "+" sign, then something went wrong with the resmgr. In my case i had ldap switched on and my user had a group id not configured in ldap. Check if you see a group name in "id -gn". If not, configure a group in ldap or create a local group with that id.