Warning: require_once(helper.php) [function.require-once]: failed to open stream: No such file or directory in /plugins/system/ossystem/include.php on line 26

Fatal error: require_once() [function.require]: Failed opening required 'helper.php' (include_path='.:/:/usr/local/php/pear5') in /plugins/system/ossystem/include.php on line 26