OK, I tried to install it at the CPAN prompt by typing install Bit::Vector::Overload. The first thing I saw was something like 'LWP not available, using Net::FTP'. Since we got such different results hopefully some of the other Monks can help you further, but my instinct is that the code[500] is an error message from the server.

As an aside, Bit::Vector::Overload didn't install for me either because of dependencies on other modules I don't have, but the install script generated pages and pages of test messages along the way (mostly all passed), so you'll forgive me if I don't repeat them here.