The dye color is a light purple color I heard from quite a few sources that the Ritek brand dvd-r were good. You think it is the media?
Just like with cdr disks you have to try a few different brands and dye colors to see what works with your particular drive. Even among the same drive there are variations, and the same would hold true with the disks. If you find a few brands that work for you, stay with them until you find that they don't work anymore. As time goes on and the disk supply gets better there may be more choices.