I'm not a perl coder, but the library support does seem pretty fantastic - http://www.cpan.org/
I don't develop on Windows or Mac, since I work on server-side software, so I might just be blissfully ignorant of a serious problem.
The documentation for those was poor. I remember the documentation for Moose being poor, as well as the documentation for Catalyst being especially bad.
And that's not even talking about the built-in documentation. Even in 1994-5 when I first learned Perl, I learned it completely from the Perl man pages and not from a book. The man pages are comprehensive, easy to read, and organized well for reference.
Ruby, Python, PHP and Node really need to get their act together and follow Perl's lead in this area.