Description:
------------
include, include_once, require, require_once generate an HTTP Error 500 (Internal 
Server Error). It would be understandable for require and require_once to 
generate these errors if the files were missing but the files are there and even 
include and include_once generate them.
I have found though that if I keep changing which of these functions I use I get 
positive results.
so for example if I try include and it fails, include_once may work instead, if 
that fails require may work instead, if that fails require_once may work. However 
i have found a situation where they have all failed and bring the error mentioned 
above.
Also have noticed that failure depends on the size of the file included. when 
files are small it works. As file size increases so does likelihood of failure

Test script:
---------------
<?php
	include('include/check_if_x_is_a_positive_integer.php');
	include('include/select_x_unique_random_y_from_database.php');
?>

Expected result:
----------------
files to be included

Actual result:
--------------
HTTP Error 500 (Internal Server Error)