Heroku + node.js error (Web process failed to bind to $PORT within 60 seconds of launch)

I have my first node.js app (runs fine locally) – but I am unable to deploy it via heroku (first time w/ heroku as well). The code is below. SO doesn’t let me write so much code, so I would just say that the running the code locally as well within my network shows no issue.

 var http = require('http');
 var fs = require('fs');
 var path = require('path');

 http.createServer(function (request, response) {

    console.log('request starting for ');
    console.log(request);

    var filePath="." + request.url;
    if (filePath == './')
        filePath="./index.html";

    console.log(filePath);
    var extname = path.extname(filePath);
    var contentType="text/html";
    switch (extname) {
        case '.js':
            contentType="text/javascript";
            break;
        case '.css':
            contentType="text/css";
            break;
    }

    path.exists(filePath, function(exists) {

        if (exists) {
            fs.readFile(filePath, function(error, content) {
                if (error) {
                    response.writeHead(500);
                    response.end();
                }
                else {
                    response.writeHead(200, { 'Content-Type': contentType });
                    response.end(content, 'utf-8');
                }
            });
        }
        else {
            response.writeHead(404);
            response.end();
        }
    });

 }).listen(5000);

 console.log('Server running at http://127.0.0.1:5000/');

Any idea ?