[racket] WeScheme cond branch error

Although the following code works perfectly well in DrRacket environment,
it generates the following error in WeScheme:
  Inside a cond branch, I expect to see a question and an answer, but I see
more than two things here.

     at: line 15, column 4, in
<definitions><http://www.wescheme.org/openEditor#>


How do I fix this? The actual code is available at
http://www.wescheme.org/view?publicId=gutsy-buddy-woken-smoke-wrest

(define (insert l n e)
  (if (= 0 n)
      (cons e l)
      (cons (car l)
            (insert (cdr l) (- n 1) e))))

(define (seq start end)
  (if (= start end)
      (list end)
      (cons start (seq (+ start 1) end))))

(define (permute l)
  (cond
    [(null? l) '(())]
    [else (define (silly1 p)
            (define (silly2 n) (insert p n (car l)))
            (map silly2 (seq 0 (length p))))
            (apply append (map silly1 (permute (cdr l))))]))
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