Module will not work with PHP 4 due to missing function array_intersect_key

When assigning a node to a header block, I received an error of the form

Fatal error: Call to undefined function array_intersect_key()

This is due to the fact the function is in PHP 5 but not in PHP 4, which I am using. However versions of this function are given in http://ie.php.net/array_intersect_key and when I pasted the function into my includes/common.inc folder all seemed to be well.

Thanks for the great module!