Hiya..
I got this error while having Native Instruments Reaktor installed (and letting the authorisation time out). Disabling it in Multimedia solved the problem. Have you checked if MIDI I/O works anyway with Mia?
What other MIDI devices are in your system? (-listdev)
HTH Soeren
Loading pd, no switches gives me: "midiInOpen: MMSYSTEM002 A device ID has been used that is out of range for your system."