Where would the error logs be?

They would be wherever you put them :)

Every perl since at least 1996 will issue that warning http://search.cpan.org/~andyd/perl5.003_07/pod/perldiag.pod#%22my%22_variable_%s_masks_earlier_declaration_in_same_scope

Perhaps now is a good time to read perlintro and perlrun

Also Tutorials > CGI Programming > CGI Help Guide, Troubleshooting Perl CGI scripts