Symphony.

Fatal error: Class 'Tidy' not found in /Users/user/Sites/xml-new/extensions/htmlformatter/extension.driver.php on line 577

$tidy = new Tidy();  /* LINE 577 */
            $tidy->parseString(
                $source, array(
                    'drop-font-tags'                => true,
                    'drop-proprietary-attributes'   => true,
                    'hide-comments'                 => true,
                    'numeric-entities'              => true,
                    'output-xhtml'                  => true,
                    'wrap'                          => 0,

                    // Stuff to get rid of awful word this:
                    'bare'                          => true,
                    'word-2000'                     => true
                ), 'utf8'
            );

            $source = $tidy->body()->value;