[plt-scheme] problems with (require ..)

Hi,

sorry for this rarther newbie question: 
I cannot seem to get the "require" command to work as described all over the docs -- say, here: http://docs.plt-scheme.org/guide/module-basics.html.

In WindowsXP DrScheme version 372, using "module" language,  
one of the first examples from the above link:

#lang scheme
(require setup/dirs)

does not work - it cannot find collection scheme. If I change scheme to mzscheme it works, but

#lang mzscheme
(require setup/dirs)

still does not work -- it says "require: unknown module: setup/dirs".

The following works under windows:

#lang mzscheme
(require "collects/setup/dirs.ss")

and 
(find-collects-dir)
returns
#<path:C:\bin\plt\collects>
(which seems to be the correct path).

Is there a way to get (require setup/dir) to work correctly for libraries distributed with drscheme?

The same issue comes up in DrScheme stable version running on Ubuntu linux (Gutsy Gibbon): evaluating

#lang scheme
(require setup/dirs)

leads to this output:

"Welcome to DrScheme, version 360.
Language: (module ...).
read: bad syntax `#l'"

Does "require" work for others for libraries in the collects directories? Help!

thanks

Rudi