title: nodejs error from app.listen() in express framework
body: <p>i dont know why im getting this error:</p>
  
  <p><img src="https://i.stack.imgur.com/pJYol.png" alt="enter image description here"></p>
  
  <p>this is my code</p>
  
  <pre><code>/*
  Chat application for @node.js
  express version.
  */
  
  //Load modules.
  var express = require('express'),
      socket = require('socket.io'),
      swig = require('swig'),
      fs = require('fs');
  
  //Load config.
  console.log('Loading configuration.');
  var config = fs.readFileSync('config.json');
  var config = JSON.parse(config);
  var port = config.port;
  var views = config.views;
  console.log('Configuration loaded.');
  console.log(config);
  
  //Initiate express module in app.
  var app = express();
  
  // app.get('/', function(request, response)
  // {
  //  fs.readFile('./views/index.html', function(error, data)
  //  {
  //      if(error)
  //      {
  //          response.send('View cannot be rendered.');
  //      }
  
  //      response.type('html');
  //      response.send(data);
  //  });
  // });
  
  var test = "Hello";
  
  app.engine('html', swig.renderFile);
  
  app.set('view engine', 'html');
  app.set('views', __dirname + '/views');
  
  swig.setDefaults(
  {
      cache: false
  });
  
  app.get('/', function(request, response)
  {
      response.render('index',
      {
          //Var to be named in the render : value;
          'test': test,
          'Title': 'Testing page',
      });
  });
  
  //logger.
  app.use(function(request, response, next)
  {
      console.log('%s %s', request.method, request.url);
      next();
  });
  
  //Set directory for static files (css, js, img)
  app.use(express.static(__dirname + '/public'));
  
  //Run the app.
  app.listen(port);
  </code></pre>
  
  <p>it might be some kind of error with the framework itself, but i dont get the clue why, i was using it last night with no error, now im getting this error this morning..</p>