Bad_namespace_prefix in stream header

i am suffering from a problem, if anyone is able to solve that, that will very helping hands for me

this error comes in warn.log file under openfire/logs

2008.06.03 17:28:04 Closing session due to bad_namespace_prefix in stream header. Prefix: jabber:server. Connection: org.jivesoftware.openfire.nio.NIOConnection@b612f8 MINA Session: (SOCKET, R: /172.32.1.1:17565, L: /172.32.5.36:5262, S: 0.0.0.0/0.0.0.0:5262)

my xmpp.domain is same as in for main domain eg. example.com

Thanks in Adv.