aref or type system bug (breaks clx on darwin x64)

I have been trying to get mcclim working on my new box, but can't get  
clx to compile.
It breaks while compiling manager.lisp, specifically on the defun for  
the cut-buffer function.
(This is all with fresh snapshot and clx download from clozure.)

I am a relatively new lisper, but have managed to narrow the problem  
down to the following form:

(let* ((buffer 0)
         (property (aref '#(:cb0 :cb1 :cb2) buffer)))
   property)

This should produce
:CB0

...and does so on sbcl-darwinx64 and openmcl-ppc.

What I get from openmcl-darwinx64 is the following error:

value (VARIABLE
        . "ccl:l1;l1-typesys.lisp.newest") is not of the expected  
type (SATISFIES
                                                                         
CCL::CTYPE-P).
    [Condition of type TYPE-ERROR]

I would appreciate any insights you may have as to solving this, as a  
brief look at the code for aref left me confused.

best regards,

Henry Irvine