--- a/mod_carbons/mod_carbons.lua	Fri Feb 24 15:38:14 2012 +0100
+++ b/mod_carbons/mod_carbons.lua	Tue Feb 28 14:20:43 2012 +0100
@@ -44,7 +44,7 @@
 
 	local bare_jid, user_sessions;
 	local no_carbon_to = {};
-	module:log("debug", "Message from %s to %s", orig_from, orig_to);
+	module:log("debug", "Message from %s to %s", tostring(orig_from), tostring(orig_to));
 	if c2s then -- Stanza sent by a local client
 		bare_jid = (origin.username.."@"..origin.host)
 		user_sessions = host_sessions[origin.username];