don't know if this was mentioned or not as i've just scanned a bit, but i think i normally "format" the dvd, then "back up files" with nero, i think the formatting just makes it so that you can add files to the disk after the initial burn, haven't done it for a while, but do need to update my backups, so i'll do it tomorrow and let you know how i did it (if i remember how)

I use DVD+RW disks by the way(not had a prob with 'em so far), and also have a samsung drive.