I assume that you haven't used CPAN as a non-root user. I would manually edit root's MyConfig.pm file and eliminate all URLs except one good mirror. Then post the contents of that file where we can see it. Later we may have to uninstall all Perl modules installed by your package manager, and then investigate your system to see what modules remain. Many monks here know lots of Perl system magic to help in the cleanup.
Update: One more option is to use cpanm instead of CPAN if we start with a system-clean configuration.