Recently I installed Alcohol120%, i was merely trying to backup a legal copy of a game of mine to store as an MDS file anyway, I use Nero7 to burn my VideoTS folders onto RW dvd's, well guess what happened when I clicked on the burn button? The drive opens with an error saying the media is incompatible, to insert a new disk. I was scratching and wondering if the dvd writing laser fried or something. I uninstalled Nero, reinstalled it. Same error. Burns to CD's though. I uninstalled a bunch of recently installed sftware, cleaned out spyware, and still had the error. Then I remembered about Alcohol, uninstalled that and bingo everything is ok again.
I had a similar problem with Alcohol 120% - incompatible media errors and unable to erase RWs. I think it had something to do with the "Ignore Media Type" setting even though I hadn't ticked it. Uninstalling and reinstalling Alcohol fixed it. I think Alcohol may use Daemon Tools virtual drive engine and people were complaining about the erasing problem on their forum.