now.js : "Object has no method" error message when trying to start server.js

I installed node.js and now.js successfully.

For now.js, this is how I did:

npm install now -g
npm install now (had to add this one. Without it, I get a "Cannot find now..." error message)

When I start the node server and provide a server.js file like this:

var httpServer = require('http');
httpServer.createServer(function (req, res) {
res.writeHead(200, {'Content-Type': 'text/html'});
res.write('Node is ok');
res.end();
}).listen(8080);
console.log('Server runs on http://xxxxx:8080/');

Everything is fine.

Now, I'm trying to add to this file a basic use of now.js:

var nowjs = require("now");
var everyone = nowjs.initialize(httpServer);

everyone.now.logStuff = function(msg){
    console.log(msg);
}

I create an index.html file in the same folder (for testing purposes)

<script type="text/javascript" src="nowjs/now.js"></script>

<script type="text/javascript">
  now.ready(function(){
    now.logStuff("Now is ok");
  });
</script>

This time, this is what I get on the terminal when starting the server:

Server runs on http://xxxxx:8080/

[TypeError: Object #<Object> has no method 'listeners']
TypeError: Object #<Object> has no method 'listeners'
    at Object.wrapServer (/home/xxxx/node_modules/now/lib/fileServer.js:23:29)
    at [object Object].initialize (/home/xxxx/node_modules/now/lib/now.js:181:14)
    at Object.<anonymous> (/home/xxxx/server.js:10:22)
    at Module._compile (module.js:444:26)
    at Object..js (module.js:462:10)
    at Module.load (module.js:351:32)
    at Function._load (module.js:309:12)
    at module.js:482:10
    at EventEmitter._tickCallback (node.js:245:11)

Please keep in mind that I'm an absolute beginner.

Thank you for your help

'npm install -g' installs modules at a global level, often with the intent of providing system-wide binaries for terminal usage. Think Ruby Gems. If you want to include a module as part of your project you need to remove the -g.

Also, your httpServer variable is not your server but rather the http module. createServer() returns a server object which you want to capture with a variable to use in your nowjs.initialize() method as follows:

var http  = require('http')
    , now = require('now')

// Returns an Http Server which can now be referenced as 'app' from now on
var app = http.createServer(
    //... blah blah blah
)

// listen() doesn't return a server object so don't pass this method call
//     as the parameter to the initialize method below
app.listen(8080, function () {
    console.log('Server listening on port %d', app.address().port)
})

// Initialize NowJS with the Http Server object as intended
var everyone = nowjs.initialize(app)