Autobahn.js - subscribe doesn't work with websockets

Question

I'm using Ratchet WebSockets and Autobahn.js for two-way client-server communication. I've installed everything, opened the ports, it's been weeks (yes, literally weeks) and it still doesn't work. I think I've narrowed it down to Autobahn's subscribe method not working correctly.

What I'm using is a slight modification of the example code found here:

http://socketo.me/docs/push

Here is my client code:

<script>
    window.define = function(factory) {
        try{ delete window.define; } catch(e){ window.define = void 0; } // IE
        window.when = factory();
    };
    window.define.amd = {};
</script>
<script src="/apps/scripts/when.js"></script> 
<script src="http://autobahn.s3.amazonaws.com/js/autobahn.min.js"></script>
<script>
    var conn = new ab.Session(
        'ws://light-speed-games.com:8080' // The host (our Ratchet WebSocket server) to connect to
      , function() {            // Once the connection has been established
            console.log('Connection established.');
            conn.subscribe('kittensCategory', function(topic, data) {
                // This is where you would add the new article to the DOM (beyond the scope of this tutorial)
                console.log('New article published to category "' + topic + '" : ' + data.title);
            });
        }
      , function() {            // When the connection is closed
            console.warn('WebSocket connection closed');
        }
      , {                       // Additional parameters, we're ignoring the WAMP sub-protocol for older browsers
            'skipSubprotocolCheck': true
        }
    );
</script>

I believe the problem lies here:

function() {            // Once the connection has been established
                console.log('Connection established.');
                conn.subscribe('kittensCategory', function(topic, data) {
                    // This is where you would add the new article to the DOM (beyond the scope of this tutorial)
                    console.log('New article published to category "' + topic + '" : ' + data.title);
                });
            }

The line console.log('Connection established.'); does its job - it logs its message in the console. However, the conn.subscribe method does nothing. It doesn't matter if I change kittensCategory to any other string, it still does nothing. But kittensCategory is the only thing that makes sense here (see Ratchet's example code through the link above).

Any ideas?

EDIT:

This is the output of ab.debug:

WAMP Connect autobahn.min.js:69
ws://light-speed-games.com:8080 autobahn.min.js:69
wamp autobahn.min.js:69
WS Receive autobahn.min.js:64
ws://light-speed-games.com:8080  [null] autobahn.min.js:64
1 autobahn.min.js:64
[0,"52cbe9d97fda2",1,"Ratchet\/0.3"] autobahn.min.js:64
WAMP Welcome autobahn.min.js:67
ws://light-speed-games.com:8080  [52cbe9d97fda2] autobahn.min.js:67
1 autobahn.min.js:67
Ratchet/0.3 autobahn.min.js:67
Connection established. client.php:15
WAMP Subscribe autobahn.min.js:74
ws://light-speed-games.com:8080  [52cbe9d97fda2] autobahn.min.js:74
kittensCategory autobahn.min.js:74
function (topic, data) {
                // This is where you would add the new article to the DOM (beyond the scope of this tutorial)
                console.log('New article published to category "' + topic + '" : ' + data.title);
            } autobahn.min.js:74
WS Send autobahn.min.js:72
ws://light-speed-games.com:8080  [52cbe9d97fda2] autobahn.min.js:72
1 autobahn.min.js:72
[5,"kittensCategory"]