Fatal error: Call to undefined function menu_execute_active_handler() in drupal 7.9 -

i in problem, site down.

fatal error: call undefined function menu_execute_active_handler()

in drupal.

please me.

as function part of essential codebase, inside includes/menu.inc, please check integrity of source code of drupal.

apart that, drupal 7.9 old, insecure release. if security updates not applied, site hacked. check page: https://www.drupal.org/drupalsa05faq

if these not help, install xdebug php extension (http://xdebug.org/) , check execution profile, xdebug can stacktrace-included errors, can lot.