[plt-scheme] Including standard functionality

For the life of me, I cannot get plt scheme to recognize a handful of
"standard functions" that are supposed to come with Scheme.
Currently I am trying to use the stream special forms
(stream-car, stream-cdr, cons-stream). In the past it has been NIL and
trace which I have had to respectively, explicity define or specify
the path. Right now I am using the "Graphical" version of scheme.
Does anyone have any suggestions?

thanks
--Gurp