&rest parameters

hi all

i am new to this group and common lisp, which i started to learn and
practice only some time ago.

if you could kindly help me with the following problem. i am writing
this function:

(defun get-day-minutes (&rest params)
(labels ((params-cons (if (= (length params) 1) t))
(h (if params-cons (caar params) (car params)))
(m (if params-cons (cdar params) (cadr params))))
(+ (* h 60) m)))

it should compute the total number of minutes if hours and minutes are
supplied as an argument. they can be supplied either as:

(get-day-minutes 3 45) or
(get-day-minutes '(3 . 45))

when calling the function i am getting the following error:

*** - APPLY: Argumentliste für SYSTEM::ERROR-OF-TYPE ist dotted (mit
"Invalid specialized parameter in method lambda list (IF (=
) 1) T): (= (LENGTH PARAMS) 1)"
am Ende).

can somebody tell what does this error mean and what is wrong with my
function definition?

thank you