G'day mastarr,

Welcome to the monastery.

Firstly, it appears you're attempting to alter the Mac OS X System Perl. If you're not, ignore the rest of this paragraph and move on to the next one; if you are, be advised that this is generally considered to be a bad idea that could potentially cause you all manner of grief. I moved to a Mac OS X system about 18 months and received the same warning (see Are there any major Perl issues with Mac OS X Lion?). For what it's worth, while there's more than one option suggested, I went with perlbrew.

For information on modules in the Bio:: namespace, you might want to look at the tutorial: Perl and Bioinformatics

There are a number of tools available for installing Perl modules. cpan and cpanp come bundled with Perl (I generally use the former).