The remote host is missing an update to ejabberd announced via advisory DSA 2033-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202033-1

It was discovered that in ejabberd, a distributed XMPP/Jabber server written in Erlang, a problem in ejabberd_c2s.erl allows remote authenticated users to cause a denial of service by sending a large number of c2s (client2server) messages that triggers an overload of the queue, which in turn causes a crash of the ejabberd daemon. For the stable distribution (lenny), this problem has been fixed in version 2.0.1-6+lenny2. For the testing distribution (squeeze), this problem has been fixed in version 2.1.2-2. For the testing distribution (sid), this problem has been fixed in version 2.1.2-2. We recommend that you upgrade your ejabberd packages.