D7 Availabilty calendar search with views exposed filter

Hi,
Firstly this is a great module and thanks for all the work in getting it to D7. I hope I'm posting in the right queue but I'm running into a problem when I set up an availability search via a Views exposed filter. I can add a " available" and get the configure filter criterion screen, but on saving the pane in Views get an error:

An AJAX HTTP error occurred.
HTTP Result Code: 500
Debugging information follows.
Path: http://localhost:8888/test.co.uk/admin/structure/views/ajax/config-item/...
StatusText: Internal Server Error
ResponseText:

On closing this pane I then get two subsequent errors:
Notice: Undefined index: in template_preprocess_views_exposed_form() (line 844 of /Applications/MAMP/htdocs/test.co.uk/sites/all/modules/views/theme/theme.inc).
Notice: Undefined variable: value in views_handler_filter_numeric->accept_exposed_input() (line 289 of /Applications/MAMP/htdocs/test.co.uk/sites/all/modules/views/handlers/views_handler_filter_numeric.inc).

I'm using Drupal 7.9 and Views 7.x-3.0-rc1.

Any help would be greatly appreciated.

Many thanks.