I have a DVD writer as my only drive but Knoppmyth won't recognize it in MythDVD. It only recognizes it as a cd drive. Under the mythdvd settings, i told mythtv to look for the dvd drive under /dev/cdrom instead of /dev/dvd but it won't work

so you're sure it is working as a cdrom drive?

if so do a ls -l /dev/cdrom and see what it is linked to , and then do ls -l /dev/dvd and make sure they are linked to the same device.