SDL_Mixer and mutliple samples not working (Vista-X-Fi)

I have a sample that loops, motor noise, and I want to have another sample
play when the user does some action. If I try to do this the second sample
will not play. If I take out the motor noise loop, then the second sample
will play… I thought SDL_Mixer was supposed to be able to play multiple
sounds? This is on Vista with X-Fi if that matters?