ok when you put the music tracks you want in the BGM folder...
right click on WAITINGROOMLOOP.mp3 or w.e it is and click rename then copy..then right click rename on your mp3 track and click paste..
Now assuming you put 2 new music tracks in the folder do the same with the uibgm thing (I forgot the names, dont feel like looking)
once you have renamed both files right click them and go to properties and be sure theres only one .mp3.
now once thats complete double click on each track for it to play and then x out of the window that played them
now it will work thank me