[plt-scheme] Internal definitions error. - Beginner.

Hi,

I seem to be getting this error:

define: expected only one expression for the function body, but found
at least one extra part

When trying to use internal definitions such as:

(define (f n)
  (define (f-w-counter n c)
    (cond
  ((< n 3) n)
  (else (* c (f-w-counter (- n 1) (- c 1))))))
  (f-w-counter n 1))

or

(define (sqrt2 x)
  (define (good-enough? guess x)
    (< (abs (- (square guess) x)) 0.001))
  (define (improve guess x)
    (average guess (/ x guess)))
  (define (sqrt-iter guess x)
    (if (good-enough? guess x)
        guess
        (sqrt-iter (improve guess x) x)))
  (sqrt-iter 1.0 x))

the latter is not mine, but from Structure and Interpretation of
Computer Programs - 1.1  The Elements of Programming. I'm not too sure
where I'm going wrong here, I understand it's something pretty basic,
but haven't managed to find an answer in the documents or PLT Scheme /
HTDP newsgroups. I've tried turning the language setting all the way
up to 11- advanced student, but no dice. I understand the error,
there's 2 expressions within the definition, but I can't see why
that's a problem.
Any help would be greatly appreciated. I understand I don't need to
use an internal definition for what I'm doing, but it would be good to
know where my confusion lies.