I had lots of problems with perl on OS X. When I first started using OS X years ago, I tried installing everything via MacPorts. Then I realised not all modules are in MacPorts, so installing either way can clobber the other. And sometimes you install something via MacPorts and it also upgrades your Perl as a dependency and now your newer version of perl can't see the old modules, so you need to install everything again, or mess around with the library paths.

A couple of months ago I installed perlbrew and cpanm and have been using that instead. So far, so good. Doesn't interfere with the system perl and doesn't interfere with any MacPorts-installed versions of perl. Problem solved (for me, at least).