xmpppy send an error
when I try to change the group of a user (I have the same error when I try to remove an agent):
DEBUG: socket sent \<iq from="asterix@jabber.lagaule.org/Gajim" type="set" id="69">\<query xmlns="jabber:iq:roster">\<item jid="tadoca%cabuzel.org@msn.jabber.lagaule.org" name="taboca">\<group>MSN\</group>\</item>\</query>\</iq>
DEBUG: socket got \<iq type='set'>\<query xmlns='jabber:iq:roster'>\<item jid='tadoca%cabuzel.org@msn.jabber.lagaule.org' name='taboca' subscription='both'>\<group>MSN\</group>\</item>\</query>\</iq>\<iq from='asterix@jabber.lagaule.org/Gajim' type='result' id='69' to='asterix@jabber.lagaule.org/Gajim'/>
DEBUG: dispatcher ok Got iq stanza
DEBUG: dispatcher ok Dispatching iq stanza with type->set props->[u'jabber:iq:roster'] id->None
DEBUG: roster ok Setting roster item tadoca%cabuzel.org@msn.jabber.lagaule.org...
DEBUG: socket sent \<iq from="asterix@jabber.lagaule.org/Gajim" type="error" id="70">\<query xmlns="jabber:iq:roster">\<item jid="tadoca%cabuzel.org@msn.jabber.lagaule.org" name="taboca" subscription="both">\<group>MSN\</group>\</item>\</query>\<error code="501" type="cancel">\<feature-not-implemented xmlns="urn:ietf:params:xml:ns:xmpp-stanzas" />\<text xmlns="urn:ietf:params:xml:ns:xmpp-stanzas">The feature requested is not implemented by the recipient or server and therefore cannot be processed.\</text>\</error>\</iq>