I use Nero extensively and have found that if i burn CD's at the full speed of my burner that I get "Bad Disc" errors and the disk gets kicked out. This is a problem with many CD Burners and the CD-R's that you are using. I kicked it down to 8X from 40X for giggles one day (I am a computer guy for a living.) and every disc I have burned at that speed has never had a problem.
FYI MP3 is a standard compression used throughout the industry. .WMA "Windows Media Audio" is for Windows Media Player, and is Micro$ofts way of trying to control the world.
