Executing Ad-Hoc Command in External Component

Hi,

I am trying to create an external component in which I need a lot of admin level information, like the list of active users in a group, registering a user, get presence of active users, etc. After reading a lot, I found that an ad-hoc command can do lot of this stuff. For this I am sendong an IQ to openfire, but I am receiving 403 error (forbidden). Below is the IQ I am sending:

<iq type="set" id="372-0" to="im.localhost.com" from="admin@component.im.localhost.com">

  <command xmlns="http://jabber.org/protocol/commands" action="execute" node="http://jabber.org/protocol/admin#get-active-users-num"/>

</iq>

Am I missing something or do I have to create an internal component to get all this information?