TypeError: Cannot call method 'insert' of null

[cadofa]

I'm pretty new to nodejs and have a trouble with it.
I use statsd to collect statistics and then send them to mongodb server for store，
but when i send the statsd's timer data to mongodb, i came across this problem.

/home/cadofa/node_modules/mongo-statsd-
backend/node_modules/mongodb/lib/mongodb/connection/base.js:245
        throw message;      
              ^
TypeError: Cannot call method 'insert' of null
    at /home/cadofa/node_modules/mongo-statsd-backend/lib/index.js:161:15
    at /home/cadofa/node_modules/mongo-statsd-
    backend/node_modules/mongodb/lib/mongodb/db.js:1011:22
    at /home/cadofa/node_modules/mongo-statsd-
    backend/node_modules/mongodb/lib/mongodb/db.js:1130:16
    at /home/cadofa/node_modules/mongo-statsd-
    backend/node_modules/mongodb/lib/mongodb/db.js:1846:9
    at Server.Base._callHandler (/home/cadofa/node_modules/mongo-statsd-
    backend/node_modules/mongodb/lib/mongodb/connection/base.js:445:41)
    at /home/cadofa/node_modules/mongo-statsd-
    backend/node_modules/mongodb/lib/mongodb/connection/server.js:478:18
    at MongoReply.parseBody (/home/cadofa/node_modules/mongo-statsd-
    backend/node_modules/mongodb/lib/mongodb/responses/mongo_reply.js:68:5)
    at null.<anonymous> (/home/cadofa/node_modules/mongo-statsd-
    backend/node_modules/mongodb/lib/mongodb/connection/server.js:436:20)
    at EventEmitter.emit (events.js:95:17)
    at null.<anonymous> (/home/cadofa/node_modules/mongo-statsd-
    backend/node_modules/mongodb/lib/mongodb/connection/connection_pool.js:201:13)

Anyone who can tell me how to solve the problem, thanks very much!

[rposbo]

This is fixed in this pull request: https://github.com/dynmeth/mongo-statsd-backend/pull/8/files