--- a/plugins/mod_s2s/mod_s2s.lua	Mon Mar 25 19:08:15 2013 +0100
+++ b/plugins/mod_s2s/mod_s2s.lua	Tue Mar 26 09:25:20 2013 +0100
@@ -486,7 +486,7 @@
 		from = from, to = to,
 	}
 	local local_host = session.direction == "outgoing" and from or to;
-	if not local_host or hosts[local_host].modules.dialback then
+	if not local_host or (hosts[local_host] and hosts[local_host].modules.dialback) then
 		attr["xmlns:db"] = 'jabber:server:dialback';
 	end