my $OpenTopic      = new Win32::API
("pmdbf32", "OpenTopic", [P, P], N);      
sub open {
    my $self  = shift;
    my $topic = shift || "-NA-";    # Topic Name provided?
    my ($lpTopic, $Topic, $return, $handle);

        # Already Open?
    return (-1) if $self->opened(@_);

        # If no topic is passed, but one was defined previously
        # then assign $topic that value
    $topic = $self->{TOPIC} if ($topic eq "-NA-") and (defined($self->{TOPIC}));

        # Return if empty Topic name
    return (-1) if ($topic eq "-NA-") and (! defined($self->{TOPIC}));

        # Allocate/Format the data
    $lpTopic = pack("L", 0);
    $Topic = pack("a16",$topic);

         #This is the line that is failing *****
    $return = $OpenTopic->Call($Topic, $lpTopic);

        # Opened Topic OK?
    if ($return == 0) {
        ($self->{HANDLE}) = unpack("L", $lpTopic);
        $self->{TOPIC} = $topic;
    } else {
        return (-1);
    }

    return $return;
}