Redirects not working

Hi

I’ve setup a WordPress site and I have come across a very strange problem. I have set up a login page for subscribers and if the login is unsuccessful I want the page to redirect back to my custom login page and not the wp-login.php page. To work around this I have added the following code to wp-login.php.

//	if ( $shake_error_codes && $wp_error->get_error_code() && //in_array( $wp_error->get_error_code(), $shake_error_codes ) )
//		add_action( 'login_head', 'wp_shake_js', 12 );

//I have replaced the code on line 55 with the following
  if ( $shake_error_codes && $wp_error->get_error_code() && in_array( $wp_error->get_error_code(), $shake_error_codes ) ){
header("Location: index.php/login?login_error=1"); exit;
   }

The redirect is not working at all, I have also used the wp_redirect()
function instead of header() and it still does not redirect.

It’s not only the wp-login page that gives this problem, I have also tested the redirects on other pages. For example on my home template page home.php I added the following code right at the top of the page for the sake of testing.

$location = 'http://www.google.com';
 wp_redirect($location);

And also

$location = 'http://www.google.com';
header("Location: $location");

I cannot see why any of the redirects would not be working