Ok I don't want to derail, but this may SEEM like I am because it's a different plug-in, but it is a Yanfly plug-in. I'll post what happened, and what worked..
I was using weapon animations yanfly plug in, and I actually used one of our wonderful community contributors weapon sprite sheets (
@whtdragon so awesome meow), and I did as the plug in instructed, and put the sprite sheets for the weapons in a custom named folder, and that didn't work. I put them in system with no weapons folder at all, and I think that worked. I also cannot check the box for unused files when I export or it breaks my game. > _ > I figure a few png files won't blow my file size out of whack so I'm not worried about it. I just need to trim all the other stuff out.
So maybe try like
@bgillisp suggested and try putting the music in a different folder?