can't mount /dev/cdrom

I can't mount /dev/cdrom. It's listed in my fstab file and there is a listing in /dev, but I get

Code:

---

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

---

when I type in

Code:

---

mount /dev/cdrom

---

. There is no cdrom listed in /mnt, and there is a directory called /dvd and /cdaudio, but I can't mount those either. Any suggestions?