Lisp parenthesis question

Question

This piece of code is from book : "Land Of Lisp" First version is from book. When I read it, i thought there are parenthesis "(" not necessary just before "at-loc-p" at 2nd line and ")" just after loc at 3rd line.

(defun person-at (loc pers per-locs)
       (labels ((at-loc-p (pers)
                 (eq (cadr (assoc pers per-locs)) loc)))
         (remove-if-not #'at-loc-p pers)))

But when I test this ,

(defun person-at (loc pers per-locs)
       (labels (at-loc-p (pers)
                 (eq (cadr (assoc pers per-locs)) loc))
         (remove-if-not #'at-loc-p pers)))

It came out :

Required arguments in AT-LOC-P don't match lambda list (CCL::FUNCNAME CCL::LAMBDA-LIST &BODY CCL::LABELS-FUNCTION-BODY).
[Condition of type CCL::SIMPLE-PROGRAM-ERROR]

I don't quiete understand. Need help. thank you.