node.js with mongodb giving error on windows while creating new db

Using following code snippet of node.js code connectiong mongodb running on windows:

var mongo = require("mongodb");
var host = "127.0.0.1";
var port = mongo.Connection.DEFAULT_PORT;

var db = new mongo.db("nodetest", new mongo.Server(host, port, {}));

db.open(function(error){
  console.log("connected" + host + ":" + port);
});

Respective error is:

C:\nodetest\mongo.js:5
var db = new mongo.db("nodetest", new mongo.Server(host, port, {}));
         ^
TypeError: undefined is not a function
    at Object.<anonymous> (C:\nodetest\mongo.js:5:10)
    at Module._compile (module.js:449:26)
    at Object.Module._extensions..js (module.js:467:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Module.runMain (module.js:492:10)
    at process.startup.processNextTick.process._tickCallback (node.js:244:9)

C:\nodetest>

Same code works on ubuntu well. Any pointers?