I've never used 'cgi-lib.pl', so I'd use CGI.pm instead ;-)
Try replacing everything from the shebang to the first if statement with:

#!/usr/bin/perl -w

eval 'exec perl -w -S $0 ${1+"$@"}'
    if 0; # not running under some shell

require 5;
use strict;
use CGI;

my $cgi = new CGI;

my $email = $cgi->param('visitor_email_address');
my $password = $cgi->param('visitor_password');

print $cgi->header('text/plain');
[download]

Also, if you want to check the validity of the email address people submit, using Email::Valid is much more reliable than using a regexp.
Hope this helps ;-)