Connection to my own Jabber server (ejabberd) fails due to it expecting only "user" and not "user@host" auth string (using SASL PLAIN). There is no way to do this because the @host part is hardcoded, but there seems to be no standard on this issue and is server-specific.

The fix is to in /includes/functions_jabber.php (457) replace:

 . base64_encode(chr(0) . $this->username . '@' . $this->server . chr(0) . $this->password) .

with:

. base64_encode(chr(0) . $this->username . chr(0) . $this->password) .