--- a/mod_storage_xmlarchive/mod_storage_xmlarchive.lua	Mon May 18 02:33:43 2015 +0200
+++ b/mod_storage_xmlarchive/mod_storage_xmlarchive.lua	Mon May 18 02:43:34 2015 +0200
@@ -24,6 +24,7 @@
 
 function archive:append(username, _, when, with, data)
 	if getmetatable(data) ~= st.stanza_mt then
+		module:log("error", "Attempt to store non-stanza object, traceback: %s", debug.traceback());
 		return nil, "unsupported-datatype";
 	end
 	username = username or "@";