faidoc

I must be missing something now

I’ve included this in my functions.php

add_action('user_register', 'auto_create_category');

function auto_create_category($user_id) {

    $category_fields = array('cat_name' => $_POST['first_name'],
	'category_description' => '',
	'category_nicename' => $_POST['first_name'],
	'category_parent' => ''
	);
	$category_fields_id = wp_insert_category($category_fields);

}

But when I register a user, the screen goes white. The user is created, but fails creating the category