I solved it. The "password" that you are prompted for is not the "passphrase" for your ssh key, but it is the user login password at the *remote* machine.
The Forrestbot deploy.scp workstage only uses the "password" method. The allowed parameters are defined http://forrest.apache.org/tools/forrestbot.html#deploy.scp The forrestbot should be enhanced at tools/forrestbot/core/deploy.xml line 66 to take advantage of the "keyfile" parameter of the "scp" Ant task. http://ant.apache.org/manual/OptionalTasks/scp.html -David
