First make sure you have created a mount point, /mnt/dvdrw or something like that, and in your fstab, perhaps you have to specify what filesystem it is, since it is DVD, it can also be udf, and not just iso9660, try adding something like this to your fstab..
Code:
/dev/hdd /mnt/dvdrw iso9660,udf noauto,users,ro 0 0
this is just an example, your dvdrw could be on hdc or something else.
