i think this is a problem between ppc and ppc2002, as i have seen it happen not only with the playsound api (and on any ppc, not only the ipaq). When you build for your 3870, do you use the ppc2002 sdk or the normal ppc sdk?
I still have not figured out what is going on and why the problem is caused, but i will post the solution here if i find it.
cryo
