Openfire is using muc#owner instead of muc#admin to change group chat affilations
Reported in forums, need confirmation: http://www.igniterealtime.org/community/message/202719#202719 :
The latest release of OpenFire does not follow the XMPP standard of using the muc#admin to change affiliation at the admin or owner level. They are still using muc#owner namespace. If you are using something like Jabber-Net you have to override the muc#admin namespace with the muc#owner namespace.