warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'search_form' I am getting a warning when I use a new theme, I've got error that search form not found.

warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'search_form' not found or invalid function name in /......./...../includes/form.inc on line 377.
Line 377
$form = call_user_func_array(isset($callback) ? $callback : $form_id, $args);

I have tried changing some items on line 377.
You need to either


Enable the core search module or 
remove the search form block from being rendered in your theme (perhaps in template.php or page.tpl.php)