Edit MIDI Mapper: 

  1) Open the Control Panel from the Windows Main program group.

  2) Double-click on MIDI Mapper.

  3) When the MIDI Mapper dialog box appears, click on Edit.

  4) Make sure that Port Name is set to "Tahiti Header Out" 
     (or "Tahiti Quad Header Out") for all sixteen channels.  
     
     If "Tahiti Header Out" does not appear in a Port Name box, 
     click on that box and an arrow will appear on the right side. 

     a) Click on the arrow and a drop down box will appear. 

     b) Click on "Tahiti Header Out."

     c) Click [OK].