It is not obvious from your post that upgrading to Perl 5.14 would be the solution.
If it is really the course of action, I would recommend you do a bit of reading as Perl as a special status within Debian (on which Raspbian is based).
https://wiki.debian.org/Perl#Perl_and_Debian
I'll risk being slightly off topic (and perhaps out of my league) to share that I have SlimServer running on Ubuntu 14.04 which probably has Perl 5.12. Although I cannot verify at this point in time, I doubt SlimServer has requirements for a much more modern version of Perl than whatever is shipped with a regular distribution. Hence my suggestion to examine more carefully the causes upstream of the Perl version.
HTH and best of luck