I would actually suggest that you update your version of Perl. The Switch module is one of the core modules that comes prepackaged with Perl, but it is possible that you have an older release of Perl that did not include it.
If you do not want to install the latest version of Perl, then you will need to install this module. If you installed ActiveState's ActivePerl, then you can use their Perl Package Manager; if you compiled Perl on your machine, then you should use the CPAN module.