Rick,
I was able to get the local server running after using your suggestion to go back in version(npm install node-persist@2.0.11)
The particle code liveimu.ino is for a Adafruit board and WiFi ,, do you have another example using the Particle Ethernet Feather Wing ? Anything simple is fine - just sending a counter to the web display if fine to understand and get the basic connections all working. No need to have sensors.
Regards, Merritt