The Yamaha AN1x Synthesizer mailing list

I just bought a game port which connects to onboard MIDI (MPU-401) 
on my PC motherboard.  When this is connected, my synth goes crazy.  
I'll play some notes and it will spontaneously transpose down a note 
and then i hit some more notes and it switches to a different voice 
altogether and pretty much goes crazy.  i'm guessing it's because of 
the MIDI connection.  

I'm wondering if this is fixable and how to fix it?  do i need to 
get a different MIDI connection altogether?  if so, what should i 
get?  how is the midisport (via USB) by m-audio?