Facebook authentication module and Alloy

Loaded the module, added the tiapp.XML code with property.

alloy.js

Alloy.Globals.Facebook = require('facebook');

// Don't forget to set your appid and requested permissions, else the login button
// won't be effective.
var fb = require('facebook');
fb.appid = XXXX_MYAPPID_XXX;
fb.permissions = ['publish_stream'];
fb.addEventListener('login', function(e) {
    if (e.success) {
        alert('Logged in');
        fb.forceDialogAuth = true;
    }
});
fb.addEventListener('logout', function(e) {
    alert('Logged out');
    var url = 'https://login.facebook.com';
});
 
 
var url = 'https://login.facebook.com';
var client = Titanium.Network.createHTTPClient();
client.clearCookies(url);
$.index.open();

<Alloy>
    <Window>
         <!-- Use the Alloy.Globals.Facebook namespace to create a Facebook module login button -->
        <LoginButton id="fbButton" ns="Alloy.Globals.Facebook"/>
    </Window>
</Alloy>

'undefined' is not an object (evaluating 'fb.appid=0x57c53122ae285') at config.js (line 44)

What's the problem ? :(