Warning: require_once(./includes/lock.inc) [function.require-once]: failed to open stream: No such file or directory in /usr/local/share/drupal6/includes/bootstrap.inc on line 1127

Fatal error: require_once() [function.require]: Failed opening required './includes/lock.inc' (include_path='.:/usr/share/php:/usr/share/pear') in /usr/local/share/drupal6/includes/bootstrap.inc on line 1127