I had the same problem. I couldn't get Addmusic revX to work at all (it always said "No music has been inserted"). However, I was able to insert some music in my hack by using Addmusic by Carol v1.12
. However, it doesn't work with all music. Some music I wanted gave a syntax error (which I had no idea how to fix in the music's txt file), but other music worked and didn't crash ZSNES when entering the level.
All I did was put the music in the "music" folder and name them the number I wanted to insert them as, then ran addmusic_e.exe, typed in the rom name (which I copied to the addmusic folder) and it worked.
BTW, even though the music works, LM shows "Not used" anyway for the music number I inserted it as. Not sure if that's normal.
Also, make sure to backup your rom before trying to insert music.