I have an error that says I do not have "Mailer.pm" in @INC

Not quite - it says that you do not have 'Mail/Mailer.pm' in @INC. As there is no 'Mail/Mailer.pm' in /usr/local/share/perl5/Mail it will not find it there. Repalce that entry in @INC with the correct one: /usr/local/share/perl5 and you will probably have more luck.