I need a backing track for an audition. URGENTLY!?

You cannot remove tracks from commercially-mixed CDs. there are people who sell machines that they claim can do this - nope. this was possible decades ago, when music was recorded differently, and the erroneous myth continues. Not vocal, not bass - you heard the rotten results for yourself. the good news is - there now exist AMPLE places where you can purchase CDs without the track that you wish to play live. And there is also Band-In-a-Box. You have time to search for these, and purchase what you wish. I do not think that SmartMusic has what you want - but you could take a quick look. good luck with the audition - but if you are going to work with digital and pre-recorded materials, then knowing their sources and limitations is just part of your craft and business.