[plt-scheme] error in letrec

To my best knowledge, I tryied to fix the following code...

But could nt...plz help me !!!!

(define one (list 10 20 30 40 50))

(list-remove
 (lambda (ls id)
   (define len (length ls))
   (letrec ((remove
            (lambda (lis)
              (if (= (length lis) id) (car lis)
                  (remove (cdr lis))
                  )
              )
            ))
     )
   (remove ls)
   )
 )

(list-remove one 2)