Warning: Cannot modify header information

bonjour,

sur mon sous wordpress et quand je veux accéder a l'administration "www.monsite.com/wp-admin" ce message d'erreur s'affiche:

Warning: Cannot modify header information - headers already sent by (output started at /home/www/web452/html/wp/w2/wp-config.php:1) in /home/www/web452/html/wp/w2/wp-includes/pluggable.php on line 1179

$status = apply_filters( 'wp_redirect_status', $status, $location );

if ( ! $location )
return false;

$location = wp_sanitize_redirect($location);

if ( !$is_IIS && php_sapi_name() != 'cgi-fcgi' )
status_header($status); // This causes problems on IIS and some FastCGI setups

header("Location: $location", true, $status);

return true;
}
endif;