Hi I've just installed Bookit on a Joomla 3.6.2; PHP 5.5.36; MySQL 5.5.52. Set up two objects for testing squash court booking. Default settings and everything work OK. As soon as I change any configuration setting the "save reservation" returns a 500 error and Page Not Working - Unable to handle request. the reservation is added to the queue.
The error log gives this message:
[Sat Sep 17 19:39:34 2016] [error] [client xxx.xxx.xxx.xxx] PHP Fatal error: Call to undefined method BookingHelper::get() in /home/xxxxxxx/public_html/squashn/administrator/components/com_booking/models/reservation.php on line 483, referer: xxxxx.xxx.xx/booking/reservation/current

If I reinstall back to defaults it's all OK again.
Any ideas?

Thanks

BTW. it's on a shared host (site5) and all permissions are 755 and 644