I am ALSO having the identical problem that w-mets has described above ==> I run the DHCPAddressPrinter verbatim as you described in the Tutorial and I get the same replay w-mets did: “Ethernet shield was not found. Sorry can’t run without hardware.”
However, I did NOT uncomment ANY of the “Ethernet.init(?)” lines at all.
The DhcpAddressPrinter sketch requires that the Controllino have an physical ethernet cable connection to a router or a device that has a DHCP server that can SUPPLY an IP address to the Controllino and then you can see what address is assigned by the router to the Controllino in the Serial Monitor.
I hope this helps you w-mat in figuring out why the program was giving you that message.