Hi Everyone,
I've had the problem since I've upgraded to Vista, I thought it was a driver problem until I had no problem burning a CD using Media Player. However I managed to find a solution (although not ideal).
If you run a CD diagnotic in iTunes, you'll find it thinks you are not an administrator for some reason. So I created a new administrator account, and then saved my iTunes library and logged in as the new administrator account. All of a sudden the problem disappeared!!!
So it looks like iTunes can't see that I'm an administrator. If someone can tell me how to fix this particular element, I'd love it. As right now, if I want to burn a CD, I have to change account, and re-import the entire library. Bottom line is it's a pain, but at least I know it's not a driver or hardware problem.
Hope this helps everyone.