The question now is why cPanel does not allow you to install (some?) modules. Without me ever using cPanel or knowing what's going on in the mind of the hosting service I would guess that the answer is "because you can mess your system very easily". You see Perl is used for some of OS maintenance and if you even upgrade system Perl or a module that system Perl relies on to be on a particular version then some things may break.

cPanel prevents me from installing any modules...I used to be able to, but the powers-that-be decided to remove compiler access. I suspect it is partly to push people to upgrade to a less restrictive hosting package as much as for security reasons. cPanel installs the modules in a user directory, not in Perl's directories so it is not an admin concern. Indeed, to use modules that have been installed, this is from cPanel within the hosting:

Your Perl script needs to know how to find the modules in your path. You can do this by adding one of the two choices below to the top of your script:

#!/usr/bin/perl
use cPanelUserConfig;
[download]

#!/usr/bin/perlml
[download]

Earlier today I installed local::lib on the suggestions of Corion which worked until I came to . ~/.bashrc which gave a "Permission denied" error. So I am rather restricted on what is possible! But, at least I now have a means of installing Perl modules without the support ticket lottery.

UPDATE:

I need to have use cPanelUserConfig; in place to be able to bring in a module that I have installed using CPAN instead of cPanel. However, that module doesn't appear in the list of installed modules displayed by cPanel.