joomla/joomla-cms — pull request #3109 by atgbcn (2014-02-14 10:32:35+00:00)
Title: Update error.php

countModules('status'))) : ?>
needs to be changed by
getInstance()->countModules('status'))) :?>

$this is, at that point, instantiated to JDocumentError which has not countModules method throwing an error.