Help - the otherwise fabulous mailgate can't ever seem to load a valid user

Greeting all.
How’s this mailgate supposed to work? Is there a design doc
or instructions other than the source? If I run
/opt/rt3/bin/rt-mailgate --debug --queue General --action correspond
–url http://localhost/rt" , it fails with

root@Valve~[5]17:14#/opt/rt3/bin/rt-mailgate --queue General --debug
–action correspond --url http://localhost
(User typed test garbage and presses ctrl-D)
/opt/rt3/bin/rt-mailgate: temp file is ‘/tmp/DM8BNyHAto’
/opt/rt3/bin/rt-mailgate: connecting to
not ok - Could not load a valid user