I found in one of my bioinformatics books (Mount, D.W., Bioinformatics sequence and genome analysis 2nd Ed.) a short bit on how to install CPAN modules:

1. create a directory eg. myperlib but remember the path name i.e /home/export/molbio/myname/myperllib
2.type -MCPAN -e shell , then configure the CPAN module, i just chose default settings where i was not sure.
3. then cpan> appears
4. configure cpan to install modules to your dir you created e.g
cpan> o conf makepl_arg LIB=/home/export/molbio/myname/myperllib
5. then ask cpan to get and install the module
cpan> install GD::Graph
6.then set perl in the direction of where to look for the installed module, note this is using perl 5, (for tcsh or csh shells)
cpan> setenv PERL5LIB/home/export/molbio/myname/myperllib
7. for bash or ssh shells
cpan> export PERL5LIB=/home/export/molbio/myname/myperllib
8. the line can also be included, if 6 and 7 fail, in the start of your script
use lib("/home/export/molbio/myname/myperllib");

this is to get CPAN to do it automatically, but as you have done, downloading the zip file, you can do it far simpler by doing it yourself:

1. Extract the files into a folder
2.type in CMD >perl Makefile.PL LIB=/home/export/molbio/myname/myperllib
>make
>make test
>make install

Hope that helps. I got stuck when it said it needed a dependant module to install, so make sure you get those also.

MonkPaul.