This might get you together if you haven't worked it out already (it is *destructive* and assumes you want to only install as root going forward, so only go for it if you're sure). As a plain user, not root-

That will remove all your current CPAN config etc. You can, of course, edit it with o conf or manually in the generated code but starting from scratch is often good. Then (I think this is good, I'm on OS X but I'm not much of a sysadmin)-

If any ENV settings turn up in there, empty them. E.g., tcsh: setenv PERL5LIB ""; or bash: export PERL5LIB="". There are a few variables that can turn up in there and mess with installs by pointing at the wrong paths and telling CPAN the wrong things are missing or already installed. Then-

And reinitialize everything. You should be good to go. Just remember to not run the cpan shell as yourself going forward.