inband registration results in 403 error

I'm trying to set up Archipel, a hypervisor that uses ejabberd. Something is wrong with my ejabberd configuration because it is unable to perform inband registration. Archipel provides a script that tests several ejabberd commands. The inband registration test fails because of a 403 Forbidden error. Here is my ejabberd.conf file:

http://pastebin.com/9cFE0fwi

Here is the error in ejabberd.log:

=INFO REPORT==== 2014-01-06 10:34:10 ===
I(<0.497.0>:ejabberd_listener:281) : (#Port<0.4344>) Accepted connection {{192,168,100,6},42523} -> {{192,168,100,6},5222}

=INFO REPORT==== 2014-01-06 10:34:11 ===
I(<0.507.0>:ejabberd_c2s:777) : ({socket_state,gen_tcp,#Port<0.4344>,<0.506.0>}) Accepted authentication for admin by ejabberd_auth_internal

=INFO REPORT==== 2014-01-06 10:34:11 ===
I(<0.507.0>:ejabberd_c2s:949) : ({socket_state,gen_tcp,#Port<0.4344>,<0.506.0>}) Opened session for admin@virthost1.example.com/configurator

=INFO REPORT==== 2014-01-06 10:34:11 ===
I(<0.497.0>:ejabberd_listener:281) : (#Port<0.4349>) Accepted connection {{192,168,100,6},42524} -> {{192,168,100,6},5222}

=INFO REPORT==== 2014-01-06 10:34:11 ===
I(<0.497.0>:ejabberd_listener:281) : (#Port<0.4351>) Accepted connection {{192,168,100,6},42525} -> {{192,168,100,6},5222}

=INFO REPORT==== 2014-01-06 10:34:11 ===
I(<0.511.0>:ejabberd_c2s:813) : ({socket_state,gen_tcp,#Port<0.4351>,<0.510.0>}) Failed authentication for dummy@virthost1.example.com from IP 192.168.100.6 ({{192,168,100,6},42525})

=INFO REPORT==== 2014-01-06 10:34:11 ===
I(<0.507.0>:ejabberd_c2s:1513) : ({socket_state,gen_tcp,#Port<0.4344>,<0.506.0>}) Close session for admin@virthost1.example.com/configurator