problem with cpan

when I want to install something in cpan on ubuntu, he said me that I haven't install YAML. I tried to install YAML via cpan but I got a Error. So looking for somewhere I find my solution:
first  update your system:

• apt-get update
• apt-get upgrade

install YAML via synaptic package manager:

• libconfig-yaml-perl

now update cpan lib's

• cpan -r

and now no more errors ..yeahhhh :P