Brasero is not writing discs
Solution 1:
I've got it.
I had the same problem as MidnightHunter burning cd's. Try to disable the first option at the burning menu; something like Burn disk image directly without saving it
(My software is in Spanish, so maybe these aren't the correct words)
Solution 2:
Yes, it's a known bug - just don't check the "burn on the fly" option. See https://bugs.launchpad.net/ubuntu/+source/brasero/+bug/780117