What's being suggested is that you maintain a private build of Perl and all your Perl modules. Your applications' shebang lines would point at a different pathname (#!/usr/local/bin/perl, for example) and the perl on /usr/local/bin would be the perl you compiled and installed yourself. That perl would look for Perl modules on a completely different set of paths where it would find your privately maintained modules.
is Perl's code repository. When you update or install new modules using the cpan command or