Error log is full of these lines:
[15-Apr-2016 18:38:57 UTC] PHP Fatal error: Call to undefined method WT_MenuBar::getCalendarMenu() in /home/gowland/public_html/kiwitrees/modules_v3/menu_calendar/module.php on line 55
[15-Apr-2016 18:38:57 UTC] PHP Fatal error: Call to a member function getClientIp() on null in /home/gowland/public_html/kiwitrees/includes/session.php on line 350
Pairs repeatedly occurring.