You can install it locally into your cgi-bin. Just download it from cpan.org and upload Calc.pm into cgi-bin/Date, then add:
use lib '.';
...into the cgi-script.
cgi-bin/colorviewpa.cgi
cgi-bn/Date/Calc.pm
use lib '.';
...into the cgi-script.
cgi-bin/colorviewpa.cgi
cgi-bn/Date/Calc.pm