[O] babel scheme not working

[Lawrence Bottorff]

 #+BEGIN_SRC scheme
(define (mydouble x)
(+ x x))

  #+END_SRC

produces

org-babel-execute-src-block: Symbol's value as variable is void:
geiser-default-implementation

also, no indentation or color coding of any sort (maybe this isn't a
feature yet?)

LB