Bigwill,
If your T.V. has a 16:9 wide screen mode select that in your tv's menue.. Then go in to your DENON dvd players menue and Select 16:9 aspect ratio. This should get rid of the jaggies. Rember dvd's native aspect ratio is 16:9 and the jaggies are produced when your dvd player changes the aspect ratio to fit a 4:3 tv screen. I have the DENON dvd 900 (DCDi) and had the same problem that you have now. I know this will work. Leave the dvd player set at 16:9 in its menue, just remember to change your tv's aspect ratio to 16:9 when you watch dvd's and 4:3 when you watch tv programs.
