M Bruner,
do you remember what type of media was used? That has an overall bigger role in your coaster problem than writing on the disc

Orsetto (in a few posts above) covered it nicely when he mentioned the data being sandwiched between two thin pieces of plastic (sony's are made like this). However I have come across older, crap dvdr's where this is not the case and they were layed out similar to a cd. So perhaps M. Bruner this was your problem? Crap media with no protection on top caused the corruption of your disc. Not so much so from the actual writing but from using cheap media, It sounds more like if anything accidently got on that dvd surface it would have screwed up your disc