[tools] Failed to read json file in cbdocloader

Install cb server 4.5.0-2524 on 4 nodes with service kv, index and n1ql
Run tools command cbdocloader to create and load gamesin-sample bucket.
Got error

[root@localhost ~]# /opt/couchbase/bin/cbdocloader -u Administrator -p password -n 172.23.107.223:8091 -b gamesim-sample -s 200 /opt/couchbase/samples/gamesim-sample.zip
...bucket creation is successful
2016-05-13 01:15:40,029: w0 Fail to read json file with error:No JSON object could be decoded
2016-05-13 01:15:40,029: w0 Fail to read json file with error:No JSON object could be decoded
.
bucket: gamesim-sample.zip, msgs transferred...
: total | last | per sec
byte : 94693 | 94693 | 261594.4
2016-05-13 01:15:45,235: mt N1QL query BUILD INDEX ON `gamesim-sample`(gamesim_primary) USING GSI failed due to ['ERROR: Internal server error, please retry your request']
done