error.php lines 35-37 read:
Pretty sure that line 36 was intended to be /css/custom.css not theme.css.
<?php if ($customCss) { ?>
<link type="text/css" rel="stylesheet" href="<?php echo TEMPLATE_URI;?>/css/theme.css" />
<?php } ?>
Pretty sure that line 36 was intended to be /css/custom.css not theme.css.