Try CGI::Session->retrieve() again?
http://cpansearch.perl.org/src/MARKSTOS/CGI-Session-4.40/examples/subscriptions.cgi

my $cgi     = new CGI();
my $session = CGI::Session->load() or die CGI::Session->errstr;

if ( $session->is_expired ) {
    print $session->header();
    print "Your session expired, inevitably!";
    exit(0);
} elsif ( $session->is_empty ) {
    $session = $session->new();
}
[download]

CGI::Session

    $s = CGI::Session->load() or die CGI::Session->errstr();
    if ( $s->is_expired ) {
        print $s->header(),
            $cgi->start_html(),
            $cgi->p("Your session timed out! Refresh the screen to sta
+rt new session!")
            $cgi->end_html();
        exit(0);
    }

    if ( $s->is_empty ) {
        $s = $s->new() or die $s->errstr;
    }
[download]