php problem not sure what is wrong

I am learning PHP and copied this piece of code from the book.

<?php
 require_once('bookmark_fns.php');
 do_html_header('');

 display_site_info(); 
 display_login_form();

 do_html_footer();
?>

I am running it in IE and I get The website cannot display the page message. I t开发者_运维技巧ried echo"hello"; and that worked fine. Any ideas of why this would not work. I wish I could give more detail, but am still unfamilair with PHP

Pop this at the top of your script, above the require_once line

error_reporting(E_ALL);
ini_set('display_errors', 'On');

My guess is something in bookmark_fns.php or the code in one of those functions is triggering an error but your configuration is set to not show any error messages.