It’s the binding order, stupid!
Recently, when I was trying to enable the automatic anti-spam updates on an Exchange Edge server, I kept getting this error:
Enable-AntispamUpdates : An error occurred while accessing the registry of the specified server: "E2K7EDGE". The error message: "The network path was not found."
After a quick search on the Internet, I didn’t find anything useful that could help solve my case. Suddenly, there was light! I remembered that my Edge server has 2 network cards and that the external interface doesn’t have “File and Printer Sharing for Microsoft Networks” and “Client for Microsoft Networks” enabled.
Bingo, that was the problem indeed. I just had to switch the binding order of the network adapters, the internal interface must *always* come first.

And that did the trick!