module mod_muc_admin : ejabberdctl create-room error

Hello,
I'

ve installed the module mod_muc_admin in order to administrate rooms.
I can delete room (ejabberdctl destroy_room room1 conference.domain.tld domain.tld), list rooms, etc,
but when I try to create on, it doesn't work, here is the error raised :
# ejabberdctl create_room room1 conference.domain.tld domain.tld
Problem 'error undef' occurred executing the command.
Stacktrace: [{mod_muc,store_room,["conference.domain.tld","room1",[]]},
{mod_muc_admin,create_room,3},
{ejabberd_ctl,call_command,3},
{ejabberd_ctl,try_call_command,3},
{ejabberd_ctl,process2,3},
{ejabberd_ctl,process,1},
{rpc,'-handle_call/3-fun-0-',5}]

Could you help me, I really don't understand why it doesn't work....

Thank you
Regards