Use this script to format the date of birth with slashes:

if (Event.Fields['Employee.EmployeeInsured.DOB'] != null) {

Event.Fields['EmpYYYY'] = Event.Fields['Engine.Employee.EmployeeInsured.DOB'].split("/")[2];

Event.Fields['EmpMM'] = Event.Fields['Engine.Employee.EmployeeInsured.DOB'].split("/")[0];

Event.Fields['EmpDD'] = Event.Fields['Engine.Employee.EmployeeInsured.DOB'].split("/")[1];

}