Have you checked cgi_error?

    my $error = $q->cgi_error;
    if ($error) {
    print $q->header(-status=>$error),
          $q->start_html('Problems'),
              $q->h2('Request not processed'),
          $q->strong($error);
        exit 0;
    }
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-Lee

"To be civilized is to deny one's nature."