Leave c:\Perl alone. Install in c:\Perl\site, or better yet, in your own perl installation. %PERLROOT%\{bin,lib,...} is typically for the base installation of the version of perl you have installed (I am guessing activestate something or another). %PERLROOT%\site\{bin,lib,...} is used when installing modules on top of that base installation.

Update: it is likely OP's own installation.

Update 2: You are dealing with two issues: first, the 401 error which is dealt with below in another response, and second, wanting to do the module installation in c:\perl instead of c:\perl\site.