I'm not sure if this will help anyone or not, but I added the following code to each .php error page in order to get my skins images/paths etc to work correctly.
FIND:
Code:
require_once('./global.php');
ADD UNDER:
Code:
// #################### HARD CODE JAVASCRIPT PATHS ########################
$headinclude = str_replace('clientscript', $vbulletin->options['bburl'] . '/clientscript', $headinclude);