It sounds like mmioOpen's documentation at http://msdn.microsoft.com/library/default.asp?url=/library/en-us/multimed/mm... is incomplete; it doesn't describe what the function does when there's no filename, just a +init, in the string passed to mmioOpen. I tried patching the source for MMIO_ParseExtA to assume an extension of "" in this case, but it didn't help, the program still exits.
I'll try to look at it. (it may not even be mmio related)
A+