there are many errors in UI logs when create XDCR replication (Server error during processing: ["web request failed",...)

there are many steps to reproduce a set of such errors but the simplest is:
on the same cluster create bucket replication

for example, in attached logs replication was from 'standard_bucket0' to "bucket0"

Server error during processing: ["web request failed",

{path,"/pools/default"}, {type,exit},
{what,
{timeout, {gen_server,call, [ns_cookie_manager,cookie_get]}}},
{trace,
[{gen_server,call,2}, {menelaus_web,build_nodes_info_fun,3}, {menelaus_web,build_pool_info,4}, {menelaus_web,handle_pool_info,2}, {menelaus_web,loop,3}, {mochiweb_http,headers,5}, {proc_lib,init_p_do_apply,3}]}] (repeated 77 times) menelaus_web019 ns_1@10.3.121.63 02:23:08 - Wed Nov 28, 2012
Server error during processing: ["web request failed",{path,"/pools/default"}

,

{type,exit},
{what,
{timeout, {gen_server,call, [ns_cookie_manager,cookie_get]}}},
{trace,
[{gen_server,call,2}, {menelaus_web,build_nodes_info_fun,3}, {menelaus_web,build_pool_info,4}, {menelaus_web,handle_pool_info_wait,5}, {menelaus_web,loop,3}, {mochiweb_http,headers,5}, {proc_lib,init_p_do_apply,3}]}] menelaus_web019 ns_1@10.3.121.63 02:22:40 - Wed Nov 28, 2012
Haven't heard from a higher priority node or a master, so I'm taking over. mb_master000 ns_1@10.3.121.64 02:22:38 - Wed Nov 28, 2012
Server error during processing: ["web request failed", {path,"/pools/default/buckets"},{type,exit}

,
{what,
{timeout,

{gen_server,call, [ns_cookie_manager,cookie_get]}}},
{trace,
[{gen_server,call,2}, {menelaus_web,build_nodes_info_fun,3}, {menelaus_web_buckets, build_bucket_node_infos,5}, {menelaus_web_buckets,build_bucket_info,5}, {menelaus_web_buckets, '-handle_bucket_list/2-lc$^0/1-0-',3},{menelaus_web_buckets, '-handle_bucket_list/2-lc$^0/1-0-',3}, {menelaus_web_buckets,handle_bucket_list,2}, {menelaus_web,loop,3}]}] menelaus_web019 ns_1@10.3.121.63 02:22:37 - Wed Nov 28, 2012
Server error during processing: ["web request failed", {path,"/pools/default"}, {type,exit},
{what,
{timeout,{gen_server,call, [ns_cookie_manager,cookie_get]}

}},
{trace,
[

{gen_server,call,2}

,

{menelaus_web,build_nodes_info_fun,3}

,

{menelaus_web,build_pool_info,4}

,

{menelaus_web,handle_pool_info,2}

,

{menelaus_web,loop,3}

,

{mochiweb_http,headers,5}

,

{proc_lib,init_p_do_apply,3}

]}] menelaus_web019 ns_1@10.3.121.63 02:22:37 - Wed Nov 28, 2012