Run mongodb in node.js without run mongod

I just want to run a Mongodb server inside node.js with this

var Db = require('mongodb').Db;
var Server = require('mongodb').Server;

var client = new Db('pixgalery00002', new Server('127.0.0.1', 27017, {}), {safe:false});

 for (var i ; i = i; i) {

   client.open(function(err, pClient) {

   if (err) throw err;

  });

 }

When I was using Mac OS X Lion, this worked. But today I upgraded to Mountain Lion, and suddenly, this doesn't work! I have to run mongod if I want to use mongodb, but I don't want that! Is a problem of mongodb in Mountain Lion? Any solution for this...?

I was using connect-mongodb as session store, but now it doesn't work too!