I am trying to use gbak or nbackup(preferred) to do a backup of a
firebird 2.0 database which is embedded.

gbak -b myDB.fdb myDB.fbk //fails "unavailable server"
gbak -b myDB.fdb myDB.fbk -user sysdba -pass masterkey //fails
"unavailable server"
The same is true of nbackup.

On my development machine, I have a classic/superserver (for
convenience). If I use the control panel applet to start the server,
the second command shown above will succeed. If I stop the server, it
fails again.

The intended deployment of this will be an embedded server. I do not
want to install a real server on the target computers.

Do either of the backup tools work with embedded servers?