compilation in allegro - or maybe not

Dear everyone,
I tried this in Allegro cl 10:

(defvar v 3)
(defvar w 19)

(defun vala (v)
  (let ((w 7))
    (print v)
    (print W)
    (mi (+ v w))))
(defun mi (mi-arg)
  (print mi-arg)
  (print v)
  (print w))

but every time i try it, just sends me back a v and w, not their values and definitely not twice. I'm a real noobie, so i cannot even imagine how many ways i can be wrong.
i can't even compile normally in Allegro. i use :cl filename.extension - is that right? please explain .. anything.

with gratitude, bubu