I've downloaded tut02.lisp, but have trouble running it.

On my machine, ccl 1.6 (windows XP, 32 bit, OpenGL 1.5) gives:

; Warning: Don't know how to setup a hook before saving cores on this Lisp.
; While executing: #<Anonymous Function #xCE06D0E>, in process listener(1).
> Error: Couldn't find function glClearColor
> While executing: CL-OPENGL-BINDINGS::GENERATE-GL-FUNCTION, in process listener
(1).
> Type :GO to continue, :POP to abort, :R for a list of available restarts.
> If continued: Skip loading "tut02.lisp"
> Type :? for other options.