Custom Taxonomy array_merge ERROR

Okay, so I am trying to add this taxonomy:

add_action('init',
'create_backgrounds_taxonomies');

function create_backgrounds_taxonomies(){
register_taxonomy(
	'categories',
	'backgrounds',
	array(
		'hierarchical' => true,
		'labels' => $labels,
		'rewrite' => array('slug' => 'categories','with_front' => true),
		'public' => true,
		'show_ui' => true,
    	'query_var' => true
		)
	);
}

it’s for a custom post type, but when I do, I get this error at the top of every page:

Warning: array_merge() [function.array-merge]: Argument #2 is not an array in /wp-includes/post.php on line 1194

Can someone help me please????
I had it working, and then all of the sudden it stopped working.