There are a few things to check. First of all, be sure you've got the MIDI OUT of the J-Station connected to the MIDI IN on your computer and vice versa. Next, be sure the switch on the back of the J-Station is in the "MIDI" position. The diagram on the back of the J-Station can be misunderstood. The "MIDI" position is where the switch is in the position closest to the MIDI jacks. Finally, be sure you've updated the firmware on your J-Station.