Subscribe COV problems

[bf89]

My Program subscribes for a analogue value, after this it waits 5 seconds(I receive the COVs in this 5 Seconds), after that I want to unsubscribe, but here I get the error "b ErrorAPDU(choice=5, errorClass=Object, errorCode=covSubscriptionFailed)" also If I try to subscribe for another value, I get this error.
What do I do wrong? I use the bacnet4j-3.2.4-API

public class Test1 {
static LocalDevice localDevice;

public static void main(String[] args) throws Exception {
	IpNetwork network = new IpNetworkBuilder().build();
	Transport transport = new DefaultTransport(network);
	localDevice = new LocalDevice(44444, transport);
	try {
		localDevice.initialize();
		localDevice.getEventHandler().addListener(new Listener());

		localDevice.sendGlobalBroadcast(new WhoIsRequest());
		Thread.sleep(2 * 1000);
		RemoteDevice device = localDevice.getRemoteDevice(2222);

		UnsignedInteger subscriberProcessIdentifier = new UnsignedInteger(0);
		UnsignedInteger lifetime = new UnsignedInteger(0);
		ObjectIdentifier oi = new ObjectIdentifier(ObjectType.analogValue,
				0);

		SubscribeCOVRequest request = new SubscribeCOVRequest(
				subscriberProcessIdentifier, oi, new Boolean(true),
				lifetime);
		localDevice.send(device, request, new ResponseConsumer() {
			@Override
			public void success(AcknowledgementService arg0) {
				System.out.println("a " + arg0);
			}
			@Override
			public void fail(AckAPDU arg0) {
				System.out.println("b " + arg0);

			}
			@Override
			public void ex(BACnetException arg0) {
				System.out.println("c " + arg0);
			}
		});

		Thread.sleep(5000);
		SubscribeCOVRequest request1 = new SubscribeCOVRequest(
				subscriberProcessIdentifier, oi, null, null);
		localDevice.send(device, request1, new ResponseConsumer() {

			@Override
			public void success(AcknowledgementService arg0) {
				System.out.println("a " + arg0);
			}
			@Override
			public void fail(AckAPDU arg0) {
				System.out.println("b " + arg0);
			}
			@Override
			public void ex(BACnetException arg0) {
				System.out.println("c " + arg0);
			}
		});

		try {
			new BufferedReader(new InputStreamReader(System.in)).readLine();
		} catch (IOException e) {
			e.printStackTrace();
		}

		localDevice.terminate();
	} catch (Exception ex) {
		ex.printStackTrace();
	}
}

static class Listener extends DeviceEventAdapter {
	@Override
	public void covNotificationReceived(
			UnsignedInteger subscriberProcessIdentifier,
			RemoteDevice initiatingDevice,
			ObjectIdentifier monitoredObjectIdentifier,
			UnsignedInteger timeRemaining,
			SequenceOf<PropertyValue> listOfValues) {

		for (int i = 0; i < listOfValues.getCount(); i++) {
			if (!(listOfValues.getValues().get(i).getValue() instanceof StatusFlags)) {
				System.out.println("COV_Result: Instance-ID:"
						+ monitoredObjectIdentifier.getInstanceNumber()
						+ " Value:"
						+ listOfValues.getValues().get(i).getValue()
						+ " Type: "
						+ monitoredObjectIdentifier.getObjectType()
								.intValue());

			}
		}
	}

	@Override
	public void iAmReceived(RemoteDevice d) {
		System.out.println("IAm received from " + d);
		System.out.println("Segmentation: " + d.getSegmentationSupported());
		d.setSegmentationSupported(Segmentation.noSegmentation);
	}
}
 }

the output of my program is;

IAm received from RemoteDevice(instanceNumber=2222, address=Address [networkNumber=20, macAddress=[ae,8,0,0,0,0]])
Segmentation: both
a null
COV_Result: Instance-ID:0 Value:2784.5 Type: 2
COV_Result: Instance-ID:0 Value:2785.0 Type: 2
COV_Result: Instance-ID:0 Value:2785.5 Type: 2
COV_Result: Instance-ID:0 Value:2786.0 Type: 2
b ErrorAPDU(choice=5, errorClass=Object, errorCode=covSubscriptionFailed)
COV_Result: Instance-ID:0 Value:2786.5 Type: 2
COV_Result: Instance-ID:0 Value:2787.0 Type: 2

EDIT: The "Problem" is that my removeDevice will be overwritten as soon as I receive the first COV. I did a workarround like that:

private RemoteDevice getRemoteDevice() {
	return localDevice.getRemoteDeviceCreate(2222, new Address(
			19, new OctetString(new byte[] { -82, 8, 0, 0, 0, 0 })));
}

this is executed any time when I send something to the bacnet server. How can I do that propperly?