Hi, welcome to the forum
There can be several causes to this. I'll let other members input about possible config problems and focus on what I know better: media.
Would you mention exactly what DVDR discs (brand, model, rated speed..) you are burning, and at what speed you burn them?
Also download DVDIdentifier and tell us what is the mediacode of these discs.
Explanation: In case your DVDRs are of poor quality, the burnt discs can or cannot be read in all drives. Some will accept them and some other will reject them (yes, it's even possible that the very drive that burned them rejects them!).