MIDI PC message issues

[KDJ3992]

My NDLR does not seem to respond to MIDI Program Change (PC) messages to select presets.  When I send the PC number, nothing happens.  I can recover the presets manually using the physical controls on the device, but I primarily control the NDLR via external MIDI foot controllers, so using the NDLR's physical controls to change presets doesn't work as well for me.  Is there something else that needs to be transmitted with the PC message?  Or some other trick?  (For example, some of my external synths require an additional MSB/LSB number be transmitted along with the PC message.)

Thanks in advance?