This can be a couple of things.
Check that you arent using a power splitter cable, linked to your DVD writer.
Dont use to many device's on one power line.
Can be cheap disks or one's that your particular drive doesn't like.
Intel Core2Duo 6400 @ 3.4Ghz
4GB Geil 6400 Ultra
3 x 500 Gb Samsung HD
EVGA 8800 Ultra OC