Node.js and Native MongoDB Connection fails

I am trying to set up a simple mongodb test server within my app.js node application but I keep getting "TypeError: Cannot read property 'arbiterOnly' of undefined". I am running it on local host and I have installed mongo db by running npm install mongodb in the folder I am making the application in. any help one what I am doing wrong would be greatly apreciated

here is my code for my application

var express = require('express')
  , routes = require('./routes')
  , user = require('./routes/user')
  , http = require('http')
  , path = require('path');
  var Db = require('mongodb').Db;
var Server = require('mongodb').Server;
var client = new Db('test', new Server('localhost:', 3100, {}));

var insertData = function(err, collection) {
    collection.insert({name: "Kristiono Setyadi"});
    collection.insert({name: "Meghan Gill"});
    collection.insert({name: "Spiderman"});
    // you can add as many object as you want into the database
}

var removeData = function(err, collection) {
    collection.remove({name: "Spiderman"});
}

var updateData = function(err, collection) {
    collection.update({name: "Kristiono Setyadi"}, {name: "Kristiono Setyadi", sex: "Male"});
}

var listAllData = function(err, collection) {
    collection.find().toArray(function(err, results) {
        console.log(results);
    });
}

var app = express();

app.configure(function(){
  app.set('port', process.env.PORT || 3000);
  app.set('views', __dirname + '/views');
  app.set('view engine', 'jade');
  app.use(express.favicon());
  app.use(express.logger('dev'));
  app.use(express.bodyParser());
  app.use(express.methodOverride());
  app.use(express.cookieParser('your secret here'));
  app.use(express.session());
  app.use(app.router);
  app.use(express.static(path.join(__dirname, 'public')));
});


client.open(function(err, pClient) {
    client.collection('test_insert', insertData);
  //  client.collection('test_insert', removeData);
    // etc.
});

var people = [{name:'Keth',age:'33',email:'ktater@gmail.com'},
{name:'Donny',age:'20',email:'donjuan86@hotmail.com'},
{name:'Loran',age:'26',email:'geegeenat@facebook.com'},
{name:'Max',age:'18',email:'axxanan@gmail.com'}];

app.configure('development', function(){
  app.use(express.errorHandler());
});

app.get('/', routes.index);
app.get('/users', user.list);
app.get('/people', function(req, res){
  res.render('peeps', {people:people});
});

app.get('/people/:id', function(req, res){
var guy;
  for (var i =0 ; i < people.length ; i++)
  {
    if(people[i].name == req.params.id)
      guy = people[i];

  }
  res.render('viewPerson', {guy:guy});
});

http.createServer(app).listen(app.get('port'), function(){
  console.log("Express server listening on port " + app.get('port'));
});