I had the same problem with the Tigase server and Asterisk; your problem is that you set:
pubsub_autocreate=yes
config in your xmpp.conf. This option causes auto creation of many nodes; if you take a look at tig_nodes in the Tigase database you will see that many nodes have been created. You must comment this option. Afterward you must redeploy your Tigase SQL schema or you have to delete all those nodes; Then everything will be fine. By looking at the debug output of res_xmpp module in the Asterisk CLI you will see that res_xmpp will try to subscribe to many nodes at once and this causes confusion because many nodes with the same name exist; and server will return 409 and 501 errors.