It's a problem with the protection it seems. If you ripped it from a CD or acquired and imported it from other (Obviously Legal...) means then you should be fine. If you downloaded it from the Itunes store however, odds are it's an m4p file (as opposed to an m4a file). This is due to the protection placed on it, and if this is the case, then you have to burn it to a CD before Audiosurf can use it. However, if any of your music is Itunes Plus Music (you know, that fancy thing that originally cost and extra 30 cents and is free now... unless you're upgrading), it should run fine. I had the same problem... I have to go buy some blank CDs now. I'd be pretty mad if they weren't so cheap.