Zend Optimizer not installed

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Fatal error: require_once() [function.require]: Failed opening required '/home/content/a/p/p/applelove/html/includes/template/left-col.inc.php' (include_path='.:/usr/local/php5/lib/php') in /home/content/a/p/p/applelove/html/sonomacountytravels/includes/template/before-content.inc.php on line 78