change line 172:
var event_date_Spry = new Spry.Widget.ValidationTextField("event_date_Spry", "date", {isRequired: false, format:'yyyy/mm/dd', validateOn:["blur"]});
to:
var event_date_Spry = new Spry.Widget.ValidationTextField("event_date_Spry", "date", {isRequired: false, format:'yyyy-mm-dd', validateOn:["blur"]});