I noticed an entry in the PHP 4 changelog which indicates that a bug in dirname() was fixed way back in PHP 4.0.3 — which is still below the minimum requirements for WordPress.
Do you know what version of PHP you have? If not, create a file called phpinfo.php in the root directory of your website and add the contents:
<?php phpinfo() ?>
Save the file and load http://www.naturalfoodworks.com/phpinfo.php in your browser to view your PHP specs. Check that the version number is at least 4.1.
