First off, this might be something related to a certain episode's level, which means the music has events set for it. Basically in the events, you can change special settings to where if this happens, than this needs to happen. Or in this case, when Bowser (npc-86) enters the screen, then the SMRPG Bowser music needs to start playing. There should be a way to edit the events in a way that it doesn't mess up the rest of the level.
Second, this is the Graphics Forum. This is where we post stuff about custom graphics to use in levels, episodes, basically whatever.
I can tell by looking at your other posts you made a second in General, which is fine, knowing you probably knew you made a mistake. I really don't wanna be a minimod, but I really like helping people out when it comes to working with SMBX, along with using the forums. Hopefully all of this was useful. =)