Never install within the system perl using both CPAN and your package manager. You WILL get conflicts. Instead, do one of two things:

1. Compile your own perl (NOT to the same location) and install CPAN modules to that.
2. Install local::lib using Synaptic, apt-get, etc... and use its abilities to create a local modules area that CPAN installs to.

I repeat. NEVER install modules within the system perl using CPAN if you have a package manager.