OK, this is because you were unable to Finalise. The only way you can use this disk, would be to find another same or similar model, and put the disc into that machine, and then select Finalise on that, this machine, should them Finalise the disc, and allow you to use it in, another DVD. Otherwise there is not much hope of using it until you can find some way of copying it. You may be able to recover some of the data with a disc recovery software on a PC, if you cannot get it finalized, in another same/similar ,machine.