> Right now, it works perfectly when reading and writing data and audio
> CDs. 

So you PROBABLY have proper permissions to use the device.  Just to
make sure, do a "ls -l /dev/hdc" and see who owns it.  If it's like my
system it'll be root:cdrom, both with rw access.  Verify that you are
in the proper group to access it, and make changes as needed.

> There is no input plugin available to handle 'dvd:/'.  Maybe MRL syntax
> is wrong or file/stream source doesn't exist.
> 
> Following the suggestion of the Xine website, I linked /dev/hdc to
> /dev/dvd, but the Xine error messages were the same before and after I
> made the link.

Instead of doing that, I went into the Xine preferences, and made the
change so that I could access "Advanced" preferences, and somewhere in
there, you have the option to change the device that is used by
default for certain things.  I just pointed the DVD section to
/dev/hdc.
After that, get yourself libdvdcss2 and/or libdvdread3, iirc.  I
believe you will need non-us sources to get those.
With those things taken care of, my computer was capable of playing
DVD's for me.

-- 
Justin Kremer <justin.kremer at gmail.com>
"We seem to have an insatiable appetite for wanting to lump incongruous
activities onto the complex task of driving." - Autoweek