CPT Registration, not working

b_affiliates_cpt.php

<?php

define('BAPT_CPT', 'b_affiliate');
define('BAPT_CTAX', 'b_aff_categories');

	class B_Affiliate_Post_Type {
		function initialize(){
			add_action( 'init',	array($this, '_init')	);
		}

		function _init(){
			
			if(is_admin()){
				$this->_register_cpt();
				$this->_register_taxonomy();
			}
			
		}


		function _register_cpt(){
		
		    $labels = array( 
		        'name' => _x( 'Affiliates', BAPT_CPT ),
		        'singular_name' => _x( 'Affiliate', BAPT_CPT ),
		        'add_new' => _x( 'Add New', BAPT_CPT ),
		        'add_new_item' => _x( 'Add New Affiliate', BAPT_CPT ),
		        'edit_item' => _x( 'Edit Affiliate', BAPT_CPT ),
		        'new_item' => _x( 'New Affiliate', BAPT_CPT ),
		        'view_item' => _x( 'View Affiliate', BAPT_CPT ),
		        'search_items' => _x( 'Search Affiliates', BAPT_CPT ),
		        'not_found' => _x( 'No affiliates found', BAPT_CPT ),
		        'not_found_in_trash' => _x( 'No affiliates found in Trash', BAPT_CPT ),
		        'parent_item_colon' => _x( 'Parent Affiliate:', BAPT_CPT ),
		        'menu_name' => _x( 'Affiliates', BAPT_CPT ),
		    );
		
		    $args = array( 
		        'labels' => $labels,
		        'hierarchical' => false,
		        'description' => 'Affiliate Custom Post Type',
		        'supports' => array( 'title', 'editor', 'excerpt', 'thumbnail', 'trackbacks', 'custom-fields', 'comments', 'revisions', 'page-attributes' ),
		        'taxonomies' => array( BAPT_CTAX ),
		        'public' => true,
		        'show_ui' => true,
		        'show_in_menu' => true,
		        'menu_position' => 20,
		        
		        'show_in_nav_menus' => true,
		        'publicly_queryable' => true,
		        'exclude_from_search' => false,
		        'has_archive' => true,
		        'can_export' => true,
		        'rewrite' => array('slug' => 'listing', 'with_front' => false),
		        'capability_type' => 'post'
		    );
		
		    register_post_type( BAPT_CPT, $args );
		}
		
		function _register_taxonomy(){
			$labels = array( 
		        'name' => _x( 'Affiliate Categories', BAPT_CTAX ),
		        'singular_name' => _x( 'Affiliate Category', BAPT_CTAX ),
		        'search_items' => _x( 'Search Affiliate Categories', BAPT_CTAX ),
		        'popular_items' => _x( 'Popular Affiliate Categories', BAPT_CTAX ),
		        'all_items' => _x( 'All Affiliate Categories', BAPT_CTAX ),
		        'parent_item' => _x( 'Parent Affiliate Category', BAPT_CTAX ),
		        'parent_item_colon' => _x( 'Parent Affiliate Category:', BAPT_CTAX ),
		        'edit_item' => _x( 'Edit Affiliate Category', BAPT_CTAX ),
		        'update_item' => _x( 'Update Affiliate Category', BAPT_CTAX ),
		        'add_new_item' => _x( 'Add New Affiliate Category', BAPT_CTAX ),
		        'new_item_name' => _x( 'New Affiliate Category', BAPT_CTAX ),
		        'separate_items_with_commas' => _x( 'Separate affiliate categories with commas', BAPT_CTAX ),
		        'add_or_remove_items' => _x( 'Add or remove affiliate categories', BAPT_CTAX ),
		        'choose_from_most_used' => _x( 'Choose from the most used affiliate categories', BAPT_CTAX ),
		        'menu_name' => _x( 'Affiliate Categories', BAPT_CTAX ),
		    );
		
		    $args = array( 
		        'labels' => $labels,
		        'public' => true,
		        'show_in_nav_menus' => true,
		        'show_ui' => true,
		        'show_tagcloud' => false,
		        'hierarchical' => true,
		
		        'rewrite' => array( 
		            'slug' => 'listing-categories',
		            'with_front' => false,
		            'hierarchical' => true
		        ),
		        'query_var' => true
		    );
		
		    register_taxonomy( BAPT_CTAX, array(BAPT_CPT), $args );
		}
	}

$bapt_plugin = new B_Affiliate_Post_Type();
$bapt_plugin->initialize();