I've seen several topics concerning that message.
Sorry, there is no 'quick fix' however.
You might try burning from the Finder. Drag the contents of the playlist to a new folder on the desktop and try to burn the folder on DVD.
Some other things to try:
Slow down burn speed.
Use other brand of DVD-R
You could also try another burning program.
Here are two which allow a limited number of burns in the trial version:
DiscBlaze and
Dragon Burn
Hope this helps.
M
17' iMac fp 800 MHz 768 MB RAM Mac OS X (10.3.9) Several ext. HD (backup and data)