Well, actually (from what I've read up on it) virgin DVD+RW's need to be formated. Right now I'm reading this guys FAQ/Manual right here http://fy.chalmers.se/~appro/linux/DVD+RW/
It has loads of great info for noob linux users(like me) who want to learn how to burn dvd's. I highly recomend you look into reading it. I actually solved my problem from the info I gained from reading that website.
my dvd rom drive is slave on my seconadry ide. So to "format" or blank the dvd I typed,
and thats it. Now the dvd disk is ready to be burned. I have been using Xcdroast to burn my cd's and dvd's and I have also played around with just using the command line to do it.
I hope this helps.