Hello mercury9 an welcome,
basically you must have libdvdcss installed, wich you can check under advanced > add software, there it should be in the list.
Maybe it's more easy to help you, if you could write a little more than,
"Tried to rip a DVD to add it to the media list, but was not successful",
what happened?( broke up during ripping, nothing happened.....)
greetz
augalex