Media problems (NEC ND-3450A)

[qanda]This thread is about the NEC ND-3450A. Click here to see full specs[/qanda]i have an _NEC DVD ±RW ND 3450A installed on a Dell 8400. I have tried unsuccessfully to burn a DVD. It will burn a CD. The program in use is Roxio. It continues to inform me that the media is wrong(not an exact quote). I am using Memorex DVD -R. I have read the other threads on the 3450a but seem to have confusing info. Please tell me in as simple terms as possible do you think that the media must be +R or +rw or is there some other problem. The drive works fine except in burning the DVD. Thanks:confused::confused: