D7 Availabilty calendar search with views exposed filter 2

Hi

I have 'Content: Availability Calendar available (exposed)' set as filter criteria in views, using latest drupal and calenadr module. However, when i try and change settings, i get the below error:

An Ajax HTTP error occurred.
HTTP Result Code: 500
Debugging information follows.
Path:../../../field_availability_calendar_cid
StatusText: Internal Server Error
Responsetext:
Fatal error: Call to a member function format() on a non-object in ../../../availability_calendar_handler_filter_availability.inc on line 116

Which means i cant change settings, and it i also cannot delete the filter.

Any ides or guidance would be greatly appreciated.

Thanks

Matt