When I insert a blank dvd-r disc, the screen says it cannot dub

If you are using a Panasonic dvd recorder you must first turn on 'high speed dunning's in the settings menu before you record the programmes. Only programmes recorded after this is enabled in settings will high speed dub. You can use 'flexible recording' to dub to dvd even if 'high speed ' is not enabled. The recorder will react a disc if something else is recorded on it and there is not enough room. Hope this helps mikeonfreeserve@hotmail.com