error code 0x8002006E DVD won't brun

I'm trying to back up my photos from iphoto onto DVD and every time I try to burn the photos I get error code 0x8002006E saying something like medium write error.
I'm copying my photos to a burn folder on the desktop first. I'm using the same DVDs. Why all of a sudden can't I back up my photos? Please help.

You could try a can of compressed air and lightly spray in the slot mine was out of warranty and I got a lens cleaner ran it a few seconds and it fixed mine if under warranty or Apple Care let them handle it.