Hi, since updating to 1.7.5 I can't create new categories anymore: [Sat Mar 23 13:43:45 2013] [error] [client 88.67.203.140] PHP Fatal error: require_once() [<a href='function.require'>function.require</a>]: Failed opening required '/lib/pubsubhubbub/publisher.php' (include_path='/var/www/vhosts/hei...