Problem with Looping MIDI Music

I’m having a weird problem with SDL_mixer. I have both SDL and
SDL_mixer included as frameworks in an OS X project, and am using
SDL_mixer to play MIDI music in-game (using the Mix_LoadMUS method)
while using SDL to play sounds. The problem is, when SDL_mixer goes
to loop the MIDI music (which SDL_mixer handles and not my own
project), this causes all sounds to cease playing. The music stops
playing, and all sounds that previously used to work stop doing so.

This is with version SDL_mixer 1.2.8 and SDL 1.2.13.

Has anybody else seen this problem? And if not, could someone point
me to the code in SDL_mixer where the MIDI music is looped, so I can
try and debug this problem on my own?

Any help would be greatly appreciated. Thanks.

– Simone