Warning: require_once(includes/config.in.php) [function.require-once]: failed to open stream: No such file or directory in D:\WEB_DATA\mainfile.php on line 22

Fatal error: require_once() [function.require]: Failed opening required 'includes/config.in.php' (include_path='.;C:\php5\pear') in D:\WEB_DATA\mainfile.php on line 22