Like so many others before me, I have moved my CPAN modules over to github.
With that being said, I would avoid using CGI::Application::Plugin::CAPTCHA at this time, at least for anything too serious. It's a suitable speed bump, but has a glaring hole you can drive a truck through. I have a fix sitting here from Cees Hek that addresses that issue. Should see a new version sometime in the near future.