WordPress MU

What I am trying to do is create an external page "sitemap.php" that lists all the pages.

<?php get_header(); ?>

<div id="content">

<div id="contentleft">

<div class="breadcrumb">
<?php if (class_exists('breadcrumb_navigation_xt')) {
echo 'Browse > ';
// New breadcrumb object
$mybreadcrumb = new breadcrumb_navigation_xt;
// Options for breadcrumb_navigation_xt
$mybreadcrumb->opt['title_blog'] = 'Home';
$mybreadcrumb->opt['separator'] = ' / ';
$mybreadcrumb->opt['singleblogpost_category_display'] = true;
// Display the breadcrumb
$mybreadcrumb->display();
} ?>
</div>

<h1>FunCityFinder SiteMap</h1>

<?php wp_list_pages('title_li='); ?>

</div>

<?php include(TEMPLATEPATH."/sidebar.php");?>

</div>

<!-- The main column ends -->

<?php get_footer(); ?>

I named this file sitemap.php and put it in my theme directory. But when I go to sitename.com/sitemap.php its goes to a 404 page...any ideas on how to get this to work?

Try:
http://site.com/wp-content/themes/yourtheme/sitemap.php

im getting a Fatal error: Call to undefined function get_header() in /home/funcity/public_html/wp-content/themes/default/sitemap.php on line 1

Any other ideas?

look for spelling errors and make sure 'function get_header' exists somewhere

Make it a page template. then go to Write Page and select it.