Nothing really new to report yet as I keep having to pull the power to my device for various reasons...although I haven't had to do it because of it misbehaving, so maybe the power in my garage could be the problem...don't know yet.
In the interim, I wanted to post a few pictures that may give more insight into my garage and my project.
First, here is the back of my board...I don't know if the way I made all those connections to +5V and GND are good practice (see the top area...I left a little bit of insulation on my +5V and GND bars to tell me which one is which):

(Note the length of the 2 bare wires...is that bad?)
Next, I noticed that around the solder joints/points of the Ethernet Shield seem to be 'dirty':

(Would that cause a problem?)
This is a small (or maybe medium) sized freezer I have plugged into the garage:

(Not that big, but could it be a problem?)
Lastly, this is my wall of network, telephone, security equipment (and there are 2 'servers' that you cannot see that I have plugged into the same outlet):

All that stuff is all plugged into that 1 electrical outlet just below my electrical panel.
I don't know if the garage door opener (and my device) are actually on the same circuit as all that stuff (or the freezer), but it might be. (It seems like it would be since it's all in the garage, but I'm not going to make any assumptions)