Something that worked for me when I became frustrated with CPAN was actually doing a fresh install. My problem was that I actually deleted a file and (due to user error on my behalf for sure) it would not reinstall it on its own.

I took the opportunity to get the latest version of Perl and the latest NET packages that I needed, and this cleared up my issue.

I dont know if this could help you but it is an option. (Note that I am fairly new to Perl, so I am sure there may be a less dramatic way of clearing this up)