Can't install express.js on BeagleBone (and npm doesn't work)

I have Rev A3 hardware
I re-installed the CircuitCo production image:


I CAN run blinkled OK.
I am using Putty to connect over my LAN


I can’t install express (although I had it working before re-installing the image) because npm says: “command not found”
I can’t install npm using: