Okay, Bruce, I'm getting the picture. However, in box one, where you said the black dimmer wire connects to the black 'load' wire, maybe you should be saying the black connects to the black 'line' wire (always-hot feed in), and the red connects to the black 'load' wire.

'Load' refers to the controlled lights, not the power feeding into the box, switch, or dimmer. I know it's semantics, but we need to speak the same language to communicate.

It looks like the mistake was connecting the purple wire to what you called the 'load' wire in box two. If that's indeed a 'load' wire, which I take to mean that it comes from the red wire in box one, then you may be overloading the dimmer in box one.

While neutral and ground are connected together in the panel, they should not be treated the same. I have to run. I'll post more later today.

Larry
www.fineelectricco.com