Cannot Post Event

I am trying to add a recurring event to http://www.VisitShelby.com. The event is for a place on the site called Bar Celona. When I created the event I started off completing the fields for making it recurring. Then I selected the business Bar Celona and had it automatically fill in the business details. Then I went through and tweaked the event description a little, selected the category, added a photo, and agreed to the terms. When i review the listing it looks fine. But when I click Publish I am brought to an http 500 error page with this url http://visitshelby.com/wp-admin/admin-ajax.php?action=geodir_ajax_action&geodir_ajax=add_listing&ajax_action=publish&listing_type=gd_event

Why can I not add events?