While I am using Slackware64 13.1, I am still using a custom 2.6.32 kernel. I just fired up gxine and it did not see my optical drive either. Couldn't find anything in Preferences to fix it. So I just did:
Code:
ln -s /dev/hda /dev/dvd
gxine now sees the dvd and played Transformers 2. Hope that was helpful.
Your optical drive in stock Slackware might just be named sr0 or something other than hda or hdb. I am not using a libata configured kernel just yet. I know nothing about creating udev rules. I guess I better be learning real quick.