header problem

Help please,

Open index page of controller, error message:

Warning (2): Cannot modify header information - headers already sent
by (output started at C:\xampp\htdocs\cake\sacweb\config\core.php:1)
[CORE\cake\libs\controller\controller.php, line 587]

Code | Context
$status = "Location: http://localhost/cake/sacweb/users/login"
header - [internal], line ??
Controller::header() - CORE\cake\libs\controller\controller.php, line
587
Controller::redirect() - CORE\cake\libs\controller\controller.php,
line 568
AuthComponent::startup() - CORE\cake\libs\controller\components
\auth.php, line 330
Component::startup() - CORE\cake\libs\controller\component.php, line
103
Dispatcher::_invoke() - CORE\cake\dispatcher.php, line 229
Dispatcher::dispatch() - CORE\cake\dispatcher.php, line 213
[main] - APP\webroot\index.php, line 90

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups "CakePHP" group.
To post to this group, send email to cake-php@googlegroups.com
To unsubscribe from this group, send email to cake-php+unsubscribe@googlegroups.com
For more options, visit this group at http://groups.google.com/group/cake-php?hl=en
-~----------~----~----~----~------~----~------~--~---