[Plugin: Posts 2 Posts] Post 2 Post not working

Hi guy!
I action plugin and dd code below in “function.php”
But Admin area and Post edit not display anything.
`function my_connection_types() {
// Make sure the Posts 2 Posts plugin is active.
if ( !function_exists( ‘p2p_register_connection_type’ ) )
return;

p2p_register_connection_type( array(
‘name’ => ‘posts_to_pages’,
‘from’ => ‘post’,
‘to’ => ‘page’
) );
}
add_action( ‘wp_loaded’, ‘my_connection_types’ );

http://ww.wp.xz.cn/extend/plugins/posts-to-posts/