I ran across an interesting issue with the ERR Dummy Locomotive board. I wanted to drive a dual-headlight dummy, but the board is obviously set up for a single LED, trying two in series or parallel didn't work well at all. I finally went to the parts bin and made a driver to give some kick to the lighting outputs. This would probably also be useful for the ERR MiniCommander 2 if you don't have the lamp output option. If you want incandescent lighting, this drives those as well, just leave out the 330 ohm resistor and use a 12V bulb in place of the two LED's.
Just thought this might help someone with a similar issue.