get XML-Parser and Simple from the links on the web page. 
Untar them.

as hurst
cd XML-Parser-2.29

perl Makefile.PL
make
make test

as root
make install

as root
cp Simple.pm /usr/lib/perl5/site_perl/XML

For most up-to-date machines you should be done. If you are running 
perl 5.004 then you may find that:

Test plot_xml_series  - complains that File/Spec.pm is missing.

get File::Spec.pm from http://search.cpan.org/search?dist=File-Spec
untar it.
cd File-Spec-0.82
perl Makefile.PL
make
make test

as root
make install


NOTE:
If you cant be root, you can put the stuff in a different area and then 
make reference to it by specifying the location with the -I flag at the top 
of the perl script. For example if you put them in /goa/perl_pm/site_perl:

#!/usr/local/bin/perl -I/goa/perl_pm/site_perl