Kairosdb error metric[0](name=abcd).tag[xyz].value

I am inserting data in kairosdb using the command: reference

bin/kairosdb.sh import -f export.txt

but in the kairosdb.log file I am getting following error:

08-10|13:54:33.443 [main] INFO  [Main.java:267] -      KairosDB service started
08-10|13:54:33.443 [main] INFO  [Main.java:268] - ------------------------------------------
08-10|14:00:38.236 [main] INFO  [TelnetServerModule.java:42] - Configuring module TelnetServerModule
08-10|14:00:39.259 [main] INFO  [CassandraHostRetryService.java:48] - Downed Host Retry service started with queue size -1 and retry delay 10s
08-10|14:00:39.357 [main] INFO  [JmxMonitor.java:52] - Registering JMX me.prettyprint.cassandra.service_kairosdb-cluster:ServiceType=hector,MonitorType=hector
08-10|14:00:39.734 [main] ERROR [Main.java:345] - metric[0](name=meterreadings).tag[building_type].value may not be empty.
08-10|14:00:40.023 [main] ERROR [Main.java:345] - metric[0](name=meterreadings).tag[building_type].value may not be empty.
08-10|14:00:40.216 [main] ERROR [Main.java:345] - metric[0](name=meterreadings).tag[building_type].value may not be empty.
08-10|14:00:40.295 [main] ERROR [Main.java:345] - metric[0](name=meterreadings).tag[building_type].value may not be empty.
08-10|14:00:40.391 [main] ERROR [Main.java:345] - metric[0](name=meterreadings).tag[building_type].value may not be empty.
08-10|14:00:40.439 [main] ERROR [Main.java:345] - metric[0](name=meterreadings).tag[building_type].value may not be empty.

My export.txt file is:

administrator@administrator-IdeaCentre-Q190:~/Abharthan/kairosdb$ head -10 export.txt
{"name": "meterreadings", "timestamp":"1359695700","tags": {"Building_id":"1","building_type":"ElementarySchool","meter_type":"temperature","unit":"F"},"value":"34.85"}
{"name": "meterreadings", "timestamp":"1359695700","tags": {"Building_id":"2","building_type":"Park","meter_type":"temperature","unit":"F"},"value":"0"}
{"name": "meterreadings", "timestamp":"1359695700","tags": {"Building_id":"3","building_type":"Industrial","meter_type":"temperature","unit":"F"},"value":"0.07"}
{"name": "meterreadings", "timestamp":"1359695700","tags": {"Building_id":"4","building_type":"RecreationCenter","meter_type":"temperature","unit":"F"},"value":"0"}
{"name": "meterreadings", "timestamp":"1359695700","tags": {"Building_id":"5","building_type":"Park","meter_type":"temperature","unit":"F"},"value":"2.2"}
{"name": "meterreadings", "timestamp":"1359695700","tags": {"Building_id":"6","building_type":"CommunityCenter","meter_type":"temperature","unit":"F"},"value":"31.41"}
{"name": "meterreadings", "timestamp":"1359695700","tags": {"Building_id":"7","building_type":"Office","meter_type":"temperature","unit":"F"},"value":"0"}
{"name": "meterreadings", "timestamp":"1359695700","tags": {"Building_id":"8","building_type":"ElementarySchool","meter_type":"temperature","unit":"F"},"value":"10.88"}
{"name": "meterreadings", "timestamp":"1359695700","tags": {"Building_id":"9","building_type":"ElementarySchool","meter_type":"temperature","unit":"F"},"value":"42.27"}
{"name": "meterreadings", "timestamp":"1359695700","tags": {"Building_id":"10","building_type":"ElementarySchool","meter_type":"temperature","unit":"F"},"value":"10.14"}

Please suggest how to fix this error.

usually the problem you describe comes from tags being provided with no associated value. TIt looks like you have values after the 10 first lines with empty value for building_type (look for "building_type":"" or similar).

By looking at your JSON I see several unrelated possible problems :

Your timestamp seems to be in Unix seconds - it should be in milliseconds (that could work with Telnet API because of OpenTSDB compatibility, but KairosDB expects milliseconds)
Your timestamp is always the same (thus you updating the same sample and again)
Your value is a String (while you'd probably like to use a long or a float), it may work but I don't recommend proceeding this way