Disc error with some DVDs

If the DVD recorder is an early model, it may be having trouble understanding some of the newer copy-protection schemes that are in use.

There's not too much you can do for this kind of problem, but you can try looking on the manufacturer's website to see if there's a firmware update for the DVD recorder. It would be something you would download and burn to a CD or DVD and then load into the recorder. That would update the DVD player's software so it can work with newer discs.