[plt-scheme] formlets...

I was very excited to see the new concept of formlets so I downloaded version  4.1.0.4-svn23sep2008 from svn and tried the example from the documentation.

The example gives the following error:

(formlet (div "Name:" (unquote (=> input-string name)) (div "Arrive:" (unquote (=> date-formlet arrive)) "Depart:" (unquote (=> date-formlet depart))) (list name arrive depart)))


The code is below:
(require web-server/formlets/formlets)
(define-struct date (month day))

(define date-formlet
  (formlet
   (div
    "Month:" ,{input-int . => . month}
    "Day:" ,{input-int . => . day})
   (make-date month day)))

(define travel-formlet
  (formlet
   (div
    "Name:" ,{input-string . => . name}
    (div
     "Arrive:" ,{date-formlet . => . arrive}
     "Depart:" ,{date-formlet . => . depart})
    (list name arrive depart))))