Completed 500 Internal Server Error in 413ms

ActionView::Template::Error (undefined method `to_key' for nil:NilClass):
    14: 
    15: function add_recurring_todo_to_active_container() {
    16:     $('#recurring_todos_container').append(html_for_recurring_todo());
    17:     $('#<%= dom_id(@recurring_todo)%>').effect('highlight', {}, 2000 );
    18:     $('#recurring-todos-empty-nd').hide();
    19: }
    20: 
  app/views/recurring_todos/create.js.erb:17:in `_app_views_recurring_todos_create_js_erb___3636683004783858558_7335200'
  app/controllers/recurring_todos_controller.rb:76:in `create'