I worked it out myself, if you go into burn mode and error message 840003f4 comes up, this is what I did.
On your left is a tv remote and above is two buttons Revue and Edit, press Edit button, then the remote disappears,
and you are left with a white screen, with the name of the Dvd on, tick the little box on the left of Dvd name. And that will do it. return to revue mode and if the Dvd plays when you press the remote play button. Its done.