The most likely cause of an error complaining about not
being able to find “cgi-lib.pl” is that MailMan is ‘lost’.
This happens when your server runs your CGI applications
with a current directory other than the actual directory
that the application is located in.  If your MailMan
installation is in “/public_html/mailman/mailman.cgi” for
instance, your server might instantiate MailMan with
“/public_html/mailman/mailman.cgi” as the current directory,
in which case everybody is happy.  It also might instantiate
MailMan with “/usr/local/somedir/” as the current
direcotory, in which case MailMan has no way of locating its
own templates and dependencies.  Luckily, there is a simple
fix for this.  At the top of the “mailman.cgi” file there is
a line that allows you to manually set the variable
“$strLocation” to an absolute path that describes the
location of your MailMan installation.  In the above example
you would set “$strLocation” to “/public_html/mailman/”,
letting MailMan know where it should look for dependencies
and templates.  Note that “$strLocation” must be a complete
directory name, with an absolute root and the terminating
“/” or “\” character, depending on your operating system and
file system.