As has been repeated on PerlMonks countless times: "Don't mess with system perl, install you own one on your home directory".
The reason is twofold:
- If you mess up something in the perl installation provided by your operating system, you operating system mit not be able to work correctly or may even fail to boot properly.
- Your operating system/package manager can update/change/remove/patch perl modules at any time, depending on the ever-changing dependencies of your installed programs. You don't want to spend hours trying to find a bug in your own programs, only to find out that your OS distributor did make some unofficial changes to some module.