AWS defaults to MAX if you don't set it to something else.
In your case, MAX is 4x and, at that speed, your burner refused to burn that crappy media. When you set it to 2.4x it was able to burn, but have you verified it? Please read this if you haven't.
By the way, you might want to try the 1.03 firmware update for your burner (remove any disc and close the tray before updating then reboot after it's finished).