Sounds like your computer does not have enough processing power left to run iTunes while you are in the game (understandably, mine does not even have enough power to run the game well.
). Maybe turn down the graphics settings a bit and go into full screen mode. And make sure that the in-game music is turned off.
Otherwise just rename your eq2.ini in your Everquest 2 folder to go back to the Default UI if you think my UI is the reason.