Thread:Extension talk:PageAttachment/Fatal Error: Class ListFiles not found/reply

Solved. Simply had to remove the // in SetupExtension.php

Also, I had to edit ui/Command.php to get the 'View Attachment History' button to work. This is the line in 'private function getViewHistoryCommandURL($fileName)' that I changed:

return $wgScriptPath. '/index.php?title=File:'. rawurldecode($fileName);