On Tue, Feb 26, 2008 at 07:08:43PM -0800, Neil Baylis wrote:

>CL-USER> (foo 3)
>> Error: value -2 is not of the expected type UNSIGNED-BYTE.
>> While executing: NBUTLAST, in process repl-thread(5).
>> Type :POP to abort, :R for a list of available restarts.
>> Type :? for other options.

Which version of CCL are you using?  I just tried this, and I get an error
popup with

  Too few arguments in call to #<Compiled-function FOO #x30004101295F>:
  1 arguments provided, at least 2 required.
     [Condition of type CCL::TOO-FEW-ARGUMENTS]

David