The CPAN is both the best and worst feature about Perl. It's great in that it gives you a huge archive of functionality you can use right now. On the other hand it also can totally screw you if a module author decides to change their API and your users update to the new module before you do. Beyond that, many Perl apps rely on other systems such as MySQL, Apache, Image Magick, Memcached, Open LDAP, etc; and those apps can sometimes be hard to install, or the user's operating system might not have binaries for the version your application needs.
This talk will explain how to solve all of these problems and reduce your support load at the same time.