Local Install with XAMPP

After following the steps and going to http://localhost/wordpress/wp-admin/install.php I get this

define(‘DB_NAME’, ‘wordpress’); // The name of the database define(‘DB_USER’, ‘root’); // Your MySQL username
define(‘DB_PASSWORD’, ”); // …and password
define(‘DB_HOST’, ‘localhost’); // 99% chance you won’t need to change this value
Fatal error: Call to undefined function is_admin() in C:\Program Files\XAMPP Lite\xampplite\htdocs\wordpress\wp-admin\includes\comment.php on line 162

any ideas would be appreciated,
Dan (a newbie)