custom post type & custom taxonomy 'add new' warnings

Hi,

Sorry in advance if any of this is basic stuff – I’m learning as I go…

I’m developing a college site where users can view courses. I want to divide courses into categories, so I’ve tried to set up the custom post type ‘Courses’ and the custom taxonomy ‘Course Category’. Here’s my code from functions.php for that:

// Registers the extra 'Courses' Menu Item
add_action( 'init', 'create_courses_post_type' );
function create_courses_post_type() {
	register_post_type( 'courses',
		array(
			'labels' => array(
			'name' => __( 'Courses' ),
			'singular_name' => __( 'Course' )
			),
			'public' => true,
			'supports' => array( 'title', 'editor' ),
			//Change the menu icon:
			'menu_icon' => get_bloginfo('template_directory') . '/images/courses16.png',
		)
	);
}

// Adds 'Course Category' taxonomy
add_action( 'init', 'create_course_kinds' );
function create_course_kinds() {
 $labels = array(
    'name' => _x( 'Course Categories', 'taxonomy general name' ),
    'singular_name' => _x( 'Course Category', 'taxonomy singular name' ),
  );
  register_taxonomy('course_kind','courses',array(
    'hierarchical' => false,
    'labels' => $labels
  ));
}

Problem is, when I try to add course categories, in this case ‘health & safety’ in the admin area I get the following 2 errors:

Warning: Invalid argument supplied for foreach() in /…/development/wp-admin/includes/plugin.php on line 1261

Warning: Cannot modify header information – headers already sent by (output started at /…/development/wp-admin/includes/plugin.php:1261) in /…/development/wp-includes/class-wp-ajax-response.php on line 129 Health & Safety

healthy and safehealth-and-safety0]]>

The line it refers to (wpadmin/includes/plugin.php:1261) is the foreach() within the code below:

/**
 * Remove a top level admin menu
 *
 * @since 3.1.0
 *
 * @param string $menu_slug The slug of the menu
 * @return array|bool The removed menu on success, False if not found
 */
function remove_menu_page( $menu_slug ) {
	global $menu;

	foreach ( $menu as $i => $item ) {
		if ( $menu_slug == $item[2] ) {
			unset( $menu[$i] );
			return $item;
		}
	}

	return false;
}

I’ve searched the forums & tried removing whitespace as suggested but I think this is a different issue. I’ve also deactivated plugins one at a time and the problem persists. I’ve also been stripping out admin menus I don’t require – could this be why I’m getting the errors?

Any help would be much appreciated!