Kibana startup error on Ubuntu 14.04

I am trying to install the ELK stack for the first time on AWS running Ubuntu 14.0.4 and using apt to install the latest stable packages and am running into some difficulties. Help would be greatly appreciated.

Elasticsearch seems to install just fine- if I curl http://localhost:9200 I get a nicely formatted bit of descriptive text. But starting Kibana (on the command line) yields:{"name":"Kibana","hostname":"ip-172-31-32-8","pid":3515,"level":60,"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. (/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":"2016-04-16T03:30:25.153Z","v":0}

The kibana.yml file appears OK:

Kibana is served by a back end server. This controls which port to use.

port: 5601

The host to bind the server to.

host: "localhost"

The Elasticsearch instance to use for all your queries.

elasticsearch_url: "http://localhost:9200"

preserve_elasticsearch_host true will send the hostname specified in elasticsearch. If you set it to false,

then the host you use to connect to this Kibana instance will be sent.

elasticsearch_preserve_host: false

Kibana uses an index in Elasticsearch to store saved searches, visualizations

and dashboards. It will create a new index if it doesn't already exist.

kibana_index: ".kibana"

If your Elasticsearch is protected with basic auth, this is the user credentials

used by the Kibana server to perform maintence on the kibana_index at statup. Your Kibana

users will still need to authenticate with Elasticsearch (which is proxied thorugh

the Kibana server)

kibana_elasticsearch_username: user

kibana_elasticsearch_password: pass

If your Elasticsearch requires client certificate and key

kibana_elasticsearch_client_crt: /path/to/your/client.crt

kibana_elasticsearch_client_key: /path/to/your/client.key

If you need to provide a CA certificate for your Elasticsarech instance, put

the path of the pem file here.

ca: /path/to/your/CA.pem

The default application to load.

default_app_id: "discover"

Time in milliseconds to wait for elasticsearch to respond to pings, defaults to

request_timeout setting

ping_timeout: 1500

Time in milliseconds to wait for responses from the back end or elasticsearch.

This must be > 0

request_timeout: 300000