Replace with the settings Facebook gives you.
d. Navigate to Set Web->Site URL & Domain -> Website Settings. Set Site URL
to yoursubdomain.yourdomain.com. Set Site Domain to your yourdomain.com.
+ e. Chose "Website" (the url should be your site URL with a trailing slash) in the
+ "Select how your app integrates with Facebook" section.
2. Enable the facebook plugin by including it in .htconfig.php - e.g.
$a->config['system']['addon'] = 'plugin1,plugin2,facebook';
3. Visit the Facebook Settings section of the "Settings->Plugin Settings" page.