It's a good practice to avoid being root if you can. I just use sudo and get the same results with a safety net. You can either run the CPAN shell using sudo to install things or use sudo on the final install step for a manual install.

perl Makefile.PL
make
make test
sudo make install
[download]

That will put the new modules in the places perl expects and make them available for everyone and you don't need to log in as root.