I’ve been trying for the life of me to implement piklist checker in my plugin, but seem to get the same response everytime I activate the plugin without piklist being downloaded. ‘Plugin Activated’

Maybe someone can help me with where its going wrong, as no matter what I try within these classes, nothing will show the ‘download piklist now’ box.
Here’s the code:

if(!class_exists('WP_piklist_fields'))
{
	class WP_piklist_fields
	{
		/**
		 * Construct the plugin object
		 */
		public function __construct()
		{
			add_action( 'init', array('WP_piklist_fields', 'init_plugin'));
		} // END public function load

		/**
		 * Init the plugin
		 */
		public static function init_plugin()
		{
			if(is_admin()) {
				include_once('piklist-checker/class-piklist-checker.php');
				if (!piklist_checker::check(__FILE__)) {
					return;
				}
			}
		} // END public static function init_plugin

		/**
		 * Activate the plugin
		 */
		public static function activate()
		{
			// Do nothing
		} // END public static function activate

		/**
		 * Deactivate the plugin
		 */
		public static function deactivate()
		{
			// Do nothing
		} // END public static function deactivate

	} // END class WP_piklist_fields
} // END if(!class_exists('WP_piklist_fields'))

if(class_exists('WP_piklist_fields'))
{
	// Installation and uninstallation hooks
	register_activation_hook(__FILE__, array('WP_piklist_fields', 'activate'));
	register_deactivation_hook(__FILE__, array('WP_piklist_fields', 'deactivate'));

	// instantiate the plugin class
	$WP_piklist_fields = new WP_piklist_fields();
}

Pre-thanks to anyone that can fix this…

Marcus