Your script has some errors, but, looking at setting cookies, I used the example in the docs. This is a simplified version, but you might want to try it something like this (shortened-version):

#!/usr/bin/perl

use strict;
use warnings;
use CGI qw/:standard/;
use DBI;
use Template;
use CGI::Ajax;
use CGI::Session;
use CGI::Cookie;
use CGI::Session::Driver::mysql;
use CGI::Carp qw(fatalsToBrowser);

my ( $src, $lib, $files );
my $cgi = new CGI;
my $ip  = $cgi->remote_host;

my $c   = new CGI::Cookie(-name    => 'foo',
                          -value   => ['bar','baz'],
                          -expires => '+3m');
print "Set-Cookie: $c\n";
print "Content-Type: text/html\n\n";                          

my $os = "$^0";
if ( $os =~ /MSWin32/ ) {
    $src   = 'D:/mixedapache/cgies/templatetoolkit/src';
    $lib   = 'D:/mixedapache/cgies/templatetoolkit/lib';
    $files = 'D:/mixedapache/cgies/templatetoolkit/';
}
else {
    $src   = '/mnt/win_d/mixedapache/cgies/templatetoolkit/src';
    $lib   = '/mnt/win_d/mixedapache/cgies/templatetoolkit/lib';
    $files = '/mnt/win_d/mixedapache/cgies/templatetoolkit/';
}
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