comments

The error must be caused by exmpp_jid:to_lower("").

I suspect the problem is, after superfeedr authorized my request with:
   
    <iq type="result" id="auth" />

it sends a
  
    <presence />

without attributions.


Then exmpp will get JidString="", then it will invoke 
exmpp_jid:to_lower(JidString). But exmpp_jid:to_lower does not expect the value,
thus mis-handles it.

erlang shell

>c(pubsub).
>pubsub:connect().
ok
    
=ERROR REPORT==== 21-Jan-2010::21:27:26 ===
** State machine <0.149.0> terminating 
** Last event in was {xmlstreamelement,
                         {xmlel,'jabber:client',[],presence,[],[]}}
** When State == logged_in
**      Data  == {state,
                     {basic,password,
                         {jid,<<"user@superfeedr.com/jkckjdsi">>,
                             <<"user">>,<<"superfeedr.com">>,<<"jkckjdsi">>},
                         "secret"},
                     {0,0},
                     false,"superfeedr.com",<0.143.0>,exmpp_tcp,#Port<0.3471>,
                     {xml_stream,
                         {gen_fsm,<0.149.0>},
                         {xml_parser,
                             [{max_size,infinity},
                              {root_depth,1},
                              {names_as_atom,true},
                              {emit_endtag,true},
                              {check_nss,xmpp},
                              {check_elems,xmpp},
                              {check_attrs,xmpp}],
                             #Port<0.3470>},
                         new,false,undefined},
                     "370793910",undefined,<0.150.0>,undefined}
** Reason for termination = 
** {bad_return_value,{jid,parse,unexpected_end_of_string,{jid,[]}}}
** exception error: {bad_return_value,{jid,parse,unexpected_end_of_string,
                                           {jid,[]}}}

pubsub.erl

%% exmpp version 0.9.2

-module(pubsub).
-export([connect/0]).

connect() ->
  exmpp:start(),
  MySession = exmpp_session:start_link(),
  Jid = exmpp_jid:make("user","superfeedr.com",random),
  exmpp_session:auth_basic(MySession,Jid,"secret"),
  {ok,_} = exmpp_session:connect_TCP(MySession,"xmpp.superfeedr.com",5222),
  exmpp_session:login(MySession).