Node-HTTP-Proxy error

I am trying to implement a node http proxy for the first time with my simple twitter tweeter. I have never used this before and tried following the docs (https://github.com/nodejitsu/node-http-proxy) with no luck. Can anyone point me in the right direction? Also, is it okay to run this locally on a mac? Thanks

var express = require('express');
var app = express();
var port = 8300;
var twitter = require('twitter');
var twit = new twitter({  keys and stuff })


var http = require('http'),
httpProxy = require('http-proxy');


twit.post('statuses/update', {status: "Hello world!"}
//this works



httpProxy.createProxyServer({target:'http://localhost:3000'}).listen(3000); 



// Create your target server--- WHat exactly does this mean??

http.createServer(function (req, res) {
  res.writeHead(200, { 'Content-Type': 'text/plain' });
  res.write('request successfully proxied!' + '\n' + JSON.stringify(req.headers, true, 2));

  res.end();
}).listen(3000);