Drupal Errors

Getting the following pretty much anytime I click something involving drupal:

warning: require_once(modules/system/system.admin.inc) [function.require-once]: failed to open stream: No such file or directory in /usr/local/ndn/web/oneclicks/drupal/includes/menu.inc on line 346.


Fatal error: require_once() [function.require]: Failed opening required ‘modules/system/system.admin.inc’ (include_path=’/usr/local/lib/php:/ndn/web/squirrelmail-1.2.7/plugins’) in /usr/local/ndn/web/oneclicks/drupal/includes/menu.inc on line 346

same here, I have a message into support, since it’s an easy-one-click, no response yet.