CouchDB error when replicating

couchdb.log

[Wed, 17 Oct 2012 08:38:45 GMT] [error] [<0.9425.0>] {error_report,<0.6443.0>,
    {<0.9425.0>,crash_report,
     [[{initial_call,{couch_rep,init,['Argument__1']}},
       {pid,<0.9425.0>},
       {registered_name,[]},
       {error_info,
           {exit,
               {badarg,
                   [{erlang,list_to_existing_atom,["data_size"]},
                    {couch_rep,'-dbinfo/1-lc$^0/1-0-',1},
                    {couch_rep,'-dbinfo/1-lc$^0/1-0-',1},
                    {couch_rep,do_init,1},
                    {couch_rep,init,1},
                    {gen_server,init_it,6},
                    {proc_lib,init_p_do_apply,3}]},
               [{gen_server,init_it,6},{proc_lib,init_p_do_apply,3}]}},
       {ancestors,
           [couch_rep_sup,couch_primary_services,couch_server_sup,<0.6444.0>]},
       {messages,[]},
       {links,[<0.6494.0>]},
       {dictionary,[]},
       {trap_exit,true},
       {status,running},
       {heap_size,2584},
       {stack_size,24},
       {reductions,1480}],
      []]}}

[Wed, 17 Oct 2012 08:38:45 GMT] [error] [<0.9407.0>] Uncaught error in HTTP request: {error,
                                 {case_clause,
                                  {error,
                                   {{badarg,
                                     [{erlang,list_to_existing_atom,
                                       ["data_size"]},
                                      {couch_rep,'-dbinfo/1-lc$^0/1-0-',1},
                                      {couch_rep,'-dbinfo/1-lc$^0/1-0-',1},
                                      {couch_rep,do_init,1},
                                      {couch_rep,init,1},
                                      {gen_server,init_it,6},
                                      {proc_lib,init_p_do_apply,3}]},
                                    {child,undefined,
                                     "7fca2f059f87ace751e48ec2451e83b8",
                                     {gen_server,start_link,
                                      [couch_rep,
                                       ["7fca2f059f87ace751e48ec2451e83b8",
                                        {[{<<"source">>,
                                           <<"http://isaacs.iriscouch.com/registry">>},
                                          {<<"target">>,<<"npm-registry">>}]},
                                        {user_ctx,null,
                                         [<<"_admin">>],
                                         <<"{couch_httpd_auth, default_authentication_handler}">>}],
                                       []]},
                                     temporary,1,worker,
                                     [couch_rep]}}}}}

[Wed, 17 Oct 2012 08:38:45 GMT] [info] [<0.9407.0>] Stacktrace: [{couch_rep,start_replication_server,1},
             {couch_rep,replicate,2},
             {couch_httpd_misc_handlers,handle_replicate_req,1},
             {couch_httpd,handle_request_int,5},
             {mochiweb_http,headers,5},
             {proc_lib,init_p_do_apply,3}]