socket.io.js not found

Please check your Express version. Express recently is updated to 3.0alpha which API was changed. If 3.0 you can change your code to something likes this:

var express = require('express')
  , http = require('http');

var app = express();
var server = http.createServer(app);
var io = require('socket.io').listen(server);

...

server.listen(8000);

Same issue with connect: https://github.com/senchalabs/connect/issues/500#issuecomment-4620773

Using with the Express 3 web framework: (from socket.io)

> Express 3 requires that you instantiate a http.Server to attach socket.io to first:

meaning - (1) you must create a server instance:

var app = express();
var http = require('http').createServer(app);

(2) couple it with the socket.io:

var io = require('socket.io');
io.listen(http);

and ONLY THEN - (3) make the server listen:

http.listen(8080);

make sure you keep this order!