CodingForums.com - Odd PHP error situation

Occasionally I've seen this error happen on a Wordpress installation I manage:

Fatal error: Call to undefined function define() in /home/blog012/public_html/index.php on line 14

What is really odd is that defiine() is a built-in PHP function. If PHP is running then the function should always be available.

Could this type of error then indicate there is something wrong elsewhere in the system, like PHP isn't configured properly?

This is the source code of index.php, there's nothing wrong with it, just posting it so we can all see that.

Code:

<?php

/**

 * Front to the WordPress application. This file doesn't do anything, but loads

 * wp-blog-header.php which does and tells WordPress to load the theme.

 *

 * @package WordPress

 */



/**

 * Tells WordPress to load the WordPress theme and output it.

 *

 * @var bool

 */

define('WP_USE_THEMES', true);



/** Loads the WordPress Environment and Template */

require('./wp-blog-header.php');

?>

Any help is appreciated, thanks! :)