cadr is a function defined in script-fu.init :
Where script-fu.init is in C:\Program Files\GIMP-2\share\gimp\2.0\scripts
So if it's saying cadr is undefined, then I'd suspect the GIMP installation.
Try this in the Scrip-fu console:
It should give the answer 2.
Code:
; Initialization file for TinySCHEME 1.40
; Per R5RS, up to four deep compositions should be defined
(define (caar x) (car (car x)))
(define (cadr x) (car (cdr x)))
(define (cdar x) (cdr (car x)))
...
So if it's saying cadr is undefined, then I'd suspect the GIMP installation.
Try this in the Scrip-fu console:
Code:
(cadr '(1 2))