cluster_run on buildbot: diag/eval/ Unexpected server error, request logged

http://qa.hq.northscale.net/job/testrunner-gerrit-master/5889/consoleFull

started from changes mentioned in http://qa.hq.northscale.net/job/testrunner-gerrit-master/5884/

simple test failed after error

[2013-04-09 15:14:13,428] - [rest_client:605] ERROR - http://127.0.0.1:9000/diag/eval/ error 500 reason: unknown ["Unexpected server error, request logged."]
[2013-04-09 15:14:13,428] - [rest_client:850] INFO - /diag/eval status on 127.0.0.1:9000: False content: ["Unexpected server error, request logged."] command: try ns_server_testrunner_api:kill_memcached(20000) catch : -> [erlang:exit(element(2, X), kill) || X <- supervisor:which_children(ns_port_sup)] end.

[menelaus:warn,2013-04-10T6:11:51.605,n_0@10.3.2.202:<0.8038.0>:menelaus_web:loop:441]Server error during processing: ["web request failed",

{path,"/diag/eval/"}

,

{type,exit}

,
{what,
{noproc,

{gen_server,call, [ns_port_sup,which_children,infinity]}

}},
{trace,
[{gen_server,call,3,
[

{file,"gen_server.erl"}

,

{line,188}

]},
{erl_eval,do_apply,6,
[

{file,"erl_eval.erl"},{line,572}]},
{erl_eval,eval_lc1,6,
[{file,"erl_eval.erl"}

,

{line,587}

]},
{erl_eval,eval_lc,6,
[

{file,"erl_eval.erl"},{line,584}]},
{erl_eval,try_clauses,8,
[{file,"erl_eval.erl"}

,

{line,789}

]},
{menelaus_web,handle_diag_eval,1,
[

{file,"src/menelaus_web.erl"},
{line,2145}]},
{menelaus_web,loop,3,
[{file,"src/menelaus_web.erl"}

,

{line,398}

]},
{mochiweb_http,headers,5,
[

{file,"mochiweb_http.erl"}

,

{line,94}

]}]}]

Please note, that on the environment cluster_run's tests run not under sudo