Kibana 4.1.1 not starting

Full error ("Error" "Error: unknown error" is not very helpful):
{"name":"Kibana","hostname":"XXXX","pid":13803,"level":50,"err":{"message":"unknown error","name":"Error","stack":"Error: unknown error\n at respond (/opt/kibana/src/node_modules/elasticsearch/src/lib/transport.js:237:15)\n at checkRespForFailure (/opt/kibana/src/node_modules/elasticsearch/src/lib/transport.js:203:7)\n at HttpConnector.<anonymous> (/opt/kibana/src/node_modules/elasticsearch/src/lib/connectors/http.js:156:7)\n at IncomingMessage.bound (/opt/kibana/src/node_modules/elasticsearch/node_modules/lodash-node/modern/internals/baseBind.js:56:17)\n at IncomingMessage.emit (events.js:117:20)\n at _stream_readable.js:944:16\n at process._tickCallback (node.js:442:13)"},"msg":"","time":"2016-01-28T22:18:13.568Z","v":0}

goes a little farther if I create the .kibana index, but then I see this in the response (in strace), and dies with same error:
"HTTP/1.1 400 Bad Request\r\nContent-Type: application/json; charset=UTF-8\r\nContent-Length: 424\r\n\r\n{\"error\":{\"root_cause\":[{\"type\":\"search_parse_exception\",\"reason\":\"No mapping found for [buildNum] in order to sort on\"}],\"type\":\"search_phase_execution_exception\",\"reason\":\"all shards failed\",\"phase\":\"query\",\"grouped\":true,\"failed_shards\":[{\"shard\":0,\"index\":\".kibana\",\"node\":\"vXXs1v-URbOh1yE4ZrB57w\",\"reason\":{\"type\":\"search_parse_exception\",\"reason\":\"No mapping found for [buildNum] in order to sort on\"}}]},\"status\":400}

Not sure why this error shows up in kibana.stdout and not kibana.stderr; shouldn't this error be to the stderr stream?