What is the problem in my custom post type code

I am creating a custom post type named product and using the code below:

function my_custom_post_product() {
	$labels = array(
		'name'               => _x( 'Products', 'post type general name' ),
		'singular_name'      => _x( 'Product', 'post type singular name' ),
		'add_new'            => _x( 'Add New', 'book' ),
		'add_new_item'       => __( 'Add New Product' ),
		'edit_item'          => __( 'Edit Product' ),
		'new_item'           => __( 'New Product' ),
		'all_items'          => __( 'All Products' ),
		'view_item'          => __( 'View Product' ),
		'search_items'       => __( 'Search Products' ),
		'not_found'          => __( 'No products found' ),
		'not_found_in_trash' => __( 'No products found in the Trash' ),
		'parent_item_colon'  => '',
		'menu_name'          => 'Products'
	);
	$args = array(
		'labels' => $labels,
		'public' => true,
		'publicly_queryable' => true,
		'show_ui' => true,
		'query_var' => true,
		'menu_icon' => get_stylesheet_directory_uri() . '/images/admin/wp-logo-small.png',
		'rewrite' => true,
		'capability_type' => 'post',
		'hierarchical' => false,
		'menu_position' => null,
		//'supports' => array('title','editor','author','thumbnail','post-thumbnails','excerpts','trackbacks','custom-fields','comments','revisions','page-attributes')
		'supports' => array('title','editor','comments','thumbnail','custom-fields',),
	);
	register_post_type( 'product', $args );
}
add_action( 'init', 'my_custom_post_product' );
function my_taxonomies_product() {
	$labels = array(
		'name'              => _x( 'Product Categories', 'taxonomy general name' ),
		'singular_name'     => _x( 'Product Category', 'taxonomy singular name' ),
		'search_items'      => __( 'Search Product Categories' ),
		'all_items'         => __( 'All Product Categories' ),
		'parent_item'       => __( 'Parent Product Category' ),
		'parent_item_colon' => __( 'Parent Product Category:' ),
		'edit_item'         => __( 'Edit Product Category' ),
		'update_item'       => __( 'Update Product Category' ),
		'add_new_item'      => __( 'Add New Product Category' ),
		'new_item_name'     => __( 'New Product Category' ),
		'menu_name'         => __( 'Product Categories' ),
	);
	$args = array(
		'hierarchical'      => true,
		'labels'            => $labels,
		'show_ui'           => true,
		'show_admin_column' => true,
		'query_var'         => true,
                'rewrite'           => array( 'slug' => 'product_category' ),
	);
	register_taxonomy( 'product_category', array( 'product' ), $args );
}
add_action( 'init', 'create_book_tax');
function create_book_tax() {
	register_taxonomy(
		'product_category',
		'product',
		array(
			'label' => __( 'Category' ),
			'rewrite' => array( 'slug' => 'product-cat' ),
			'hierarchical' => true,
		)
	);
}

Please tell me, am i doing any mistake because after this my website unable to open.. ??

Thanks for any body who can solve it..