I assume you have checked out your DVD drive and it is operating properly otherwise? It is listed in Disk Utility (grayed out if no disc is in it)? It shows up and says it has burning capabilities in Apple/About this Mac/System Report/ Disc Burning (or the equivalent place if you are not running Lion)? Does it give the same error if you burn a file to a blank disc from Finder?
Another posted solution is to repair permissions on your HD in Disk Utility.
Another post was about running virtualization software at the same time (Parallels or Fusion, for example). They can take control of the burner.
I'll keep searching for a solution on the forum but 99% of the reports on this error message have to do with iTunes for Windows. Most of the ones for Mac are posts of the problem but no responses.