Spamassassin and DNS

Hi,
I am trying to follow along with the instructions for Installing v3.1.0 into your account. I made it through the Spamassassin guide ok but I'm having some trouble with the section with cpan installs. Specifically, step 4 says

Run export PERL5LIB=$HOME/local/lib/perl/5.8.4/:$HOME/local/share/perl/5.8.4/ 
so that cpan can find modules that it installs (when checking dependencies)

What exactly do I need to use here? I assume I am supposed to replace local with something but what?
I tried using /usr/lib/perl/5.8.4/:/usr/share/perl/5.8.4/ but I still get errors on the installs.
Install Mail::DomainKeys gets this at the end

Running make install
  make test had returned bad status, won't install without force

Can somebody give a little more detailed explanation and assist us newbie types who aren't familiar with things like CPAN Installs?

You don't need to change "local" to anything. The intent is that you will create a directory called local in your home directory, and install SpamAssassin and any other Perl modules it needs in that directory.