Maxima with Corman CL - defsystem defsetf bug

Hi Maxima Lisp experts.

I'm using James' pure Lisp build mechanism with Corman CL, but running into
trouble with defsetf get-system in "defsystem.lisp" in the function
"create-component".

I've inserted a format statement just before the problem statement as
follows:

...
    (format t "name = ~A ; component = ~A ; ~A ~A ~A ~A" name component (eq
type :defsystem) (eq type :system) (eq type :subsystem) (get-system name))
    ;; Type specific setup:
    (when (or (eq type :defsystem) (eq type :system) (eq type :subsystem))
      (setf (get-system name) component))
...

With Corman CL this gives:

===================================================================
name = maxima ; component = #<DEFSYSTEM: maxima> ; T NIL NIL NIL;;; An error
occurred in function (SETF GET-SYSTEM):
;;; Error: Not a list: maxima
;;; Entering Corman Lisp debug loop.
;;; Use :C followed by an option to exit. Type :HELP for help.
;;; Restart options:
;;; 1   Abort to top level.
===================================================================

With GCL the printout is the same but there is, of course, no problem:

===================================================================
name = maxima ; component = #<DEFSYSTEM: maxima> ; T NIL NIL NIL
===================================================================

I am at the limits of my understanding of CL here and would appreciate any
advice as to how to understand and isolate this bug in Corman CL.

Cheers

Mike Thomas.