[plt-scheme] Let, cond and local

Hi All,

I'm getting a little confused, in the Revised5 Report on the Algorithmic
Language Scheme, on section 4.2.2 the constructs let, let* and letrec
are described. But in the first line of my "homework" already in the
first line I get the error msg:

function call: expected a defined name or a primitive operation name
after an open parenthesis, but found something else in: (m (cond (((<=
1800 j 1899) 23) ((<= 1900 j 2199) 24) (else (error "falsches Jahr")))))

Then consulting one of the resources listed by Ferguson and Jim
(www.htdp.org) in the index of the book there is no mention of the let,
let* and letrec, but I found something similar: local, which I cannot
find any reference to it in the Revised5 Report, btw the construct cond
uses "(" in the Revised5 Report while in the htdp.org it uses "[", does
it matter??

Then:
- Aren't the Revised5 Report and the htdp.org talking about the same
Scheme?
- Why did I get this error-msg using let?
(I'm using DrScheme Beginning Student)

-----------
I guess that the nested let* is wrong, but I cannot pass through the
first...

(define (oster j) (let* ((m (cond (((<= 1800 j 1899) 23)
                                   ((<= 1900 j 2199) 24)
                                   (else (error "falsches Jahr")))))
                         (n (cond (((<= 1800 j 1899) 4)
                                   ((<= 1900 j 2099) 5)
                                   ((<= 2100 j 2199) 6))))
                         (a (modulo j 19))
                         (b (modulo j 4))
                         (c (modulo j 7))
                         (d (modulo (+ (* 19 a) m) 30))
                         (e (modulo (+ (* 2 b) (* 4 c) (* 6 d) n) 7)))
                    (let* (tag (if (> (+ d e) 9) (+ d e -9) (+ 22 d e)))
                      (monat (if (> (+ d e) 9) 'April 'Maerz))))
  (if (= monat 'April) (cond ((= tag 26) (list 19 monat j))
                             ((and (= tag 25) (= d 28) (= e 6) (> a 9))
(list 18 monat j)) (list tag monat j))))
----------------

TIA,

        ________________ _..----====~~~~====--,
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----- `---'---._________.' Ricardo Massamitsu Nonomura
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