[plt-scheme] plot's keyword arguments

Hi folks,

This may be a newbie error.  I'm in the Pretty Big language, and say
    require 'plot'
then copy-paste the example from
   http://docs.plt-scheme.org/plot/Quick_Start.html#%28part._.Basic_.Plotting%29

    (plot (line (lambda (x) (sin x)))
          #:x-min -1 #:x-max 1 #:title "Sin(x)")

and get the error
    procedure plot: expects 1 argument plus optional arguments with keywords
    #:bgcolor, #:fgcolor, #:height, #:lncolor, #:out-file, #:title, #:width,
    #:x-label, #:x-max, #:x-min, #:y-label, #:y-max, and #:y-min, given 7:
    #<procedure> #:x-min -1 #:x-max 1 #:title "Sin(x)"

    (version)
    "4.2"

Am I doing something wrong?

Thanks,
Grem

-- 
------ __@   Gregory A. Marton                 http://csail.mit.edu/~gremio
--- _`\<,_                                                     617-775-3005
-- (*)/ (*)            Guns cause crime like matches cause arson.
~~~~~~~~~~~~~~~~-~~~~~~~~_~~~_~~~~~v~~~~^^^^~~~~~--~~~~~~~~~~~~~~~++~~~~~~~