XMPP MUC Room not available unless Admin account joins room

Please excuse the cross posting - as part of my mission to properly control ejabberd from a php application, I have installed xmlrpc and am using this with *some* success.

Am having a specific problem, posted to stack overflow here: http://stackoverflow.com/questions/29472269/xmpp-muc-room-not-available-...

I don't know whether I am failing to understand muc configuration, problems with my code or xmlrpc issues.

Thanks for any help here or there..