Trying to query MongoDB through node.js but keep getting weird error

I keep getting an error in regards to querying MongoDB:

var MongoClient = require('mongodb').MongoClient;
//assert = require('assert');


// Connection URL 
var url = 'mongodb://localhost:27017/myproject';
// Use connect method to connect to the Server 
 MongoClient.connect(url, function(err, db) {
//assert.equal(null, err);
if(err)
 throw err;
else{
console.log("Connected correctly to server");
var cursor = db.collection('documents').find({'_id':'01'});
cursor.forEach(function(err,doc) {
  if(err){
      throw err;
  } else{
      console.log(doc);
 }});
db.close();

}});

The error I am getting is this.

process.nextTick(function(){ throw err;});

[object Object]

Any help is appreciated! Thanks.

via Ong Kong Tat