Helen,

HB> As I'm sure you already know, Nando, the localhost IP address on one
HB> machine is not visible to any other machine.

Correct. The "localhost" name and the "127.0.0.1" are mapped to the
loopback interface.

HB> So if he's trying to access
HB> the database from his remote machine as "127.0.0.1"

He's not. He's RDPing, which means it's not on "his machine" anymore.
He's on the server.

HB> the server that he
HB> "registered" (presumably in IBConsole or some other tool that "registers
HB> servers" is known only on the machine where the "registration" was
HB> done.

Yes.

HB> It's not known to remote clients (which have their own localhost at
HB> that address)

Correct.

HB> and it's not known to a Remote Desktop client, even if that
HB> client is on the same physical machine as this "registered server".

Wrong.

Ciao
--
Nando Dessena
http://www.flamerobin.org