CGI.pm (must be upper-cased) is part of the perl distribution, you shouldn't have to install it separately. Try to just use it in a module (use CGI;) with the proper upper-casing. If that doesn't solve things, you'll need to tell us what OS you are on and whether you are using CPAN.pm, CPANPLUS.pm, ppm, apt-get, rpm, or just plain make since those are all possible ways to install a module.