Set time zone environment variable to "GMT"?

How does one "set the time zone environment variable to 'GMT'" under 
Windows XP?  The fCalendar documentation says repeatedly that this is 
required, but Brian Ripley said it's impossible 
(http://finzi.psych.upenn.edu/R/Rhelp02a/archive/47054.html).

	  Thanks,
	  spencer graves

Spencer Graves, PhD
Senior Development Engineer
PDF Solutions, Inc.
333 West San Carlos Street Suite 700
San Jose, CA 95110, USA

spencer.graves at pdf.com
www.pdf.com <http://www.pdf.com>
Tel:  408-938-4420
Fax: 408-280-7915