ITX bug

I have a template script which crashes Apache on my server and at DH. Anybody have any idea what I am doing wrong here?

Contents of quiz.php

<?php set_include_path(get_include_path() . PATH_SEPARATOR . "/usr/local/lib/php" ); // include class require_once ('HTML/Template/IT.php'); class quiz extends HTML_Template_IT { function __construct() { // create object // set template directory $this->HTML_Template_IT("templates/"); // load template $this->loadTemplateFile("quiz.tpl"); } function show() { // set block $this->setCurrentBlock("main"); // assign values $this->setVariable("QUESTION", "Knock, knock!"); $this->setVariable("ANSWER", "Who's there?"); // parse block $this->parseCurrentBlock(); // render page $this->show(); } } $quiz = new quiz(); $quiz->show(); ?>

Contents of quiz.tpl