WordPress 3.5 how to determine if user is on category listing or category edit screen?

if(is_admin() && isset($_GET['taxonomy']) && $_GET['taxonomy'] == 'category' && isset($_GET['tag_ID']) {
    // place your code here
}

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)