can't reassign task !

Hi everybody!

is here my code :

try{
//Set connection properties
Properties ConnectionProps = new Properties();
ConnectionProps.setProperty(ServiceClientFactoryProperties.DSC_DEFAULT_EJB_ENDPOINT, "jnp://172.31.196.43:1099");
ConnectionProps.setProperty(ServiceClientFactoryProperties.DSC_TRANSPORT_PROTOCOL,Service ClientFactoryProperties.DSC_EJB_PROTOCOL);
ConnectionProps.setProperty(ServiceClientFactoryProperties.DSC_SERVER_TYPE, ServiceClientFactoryProperties.DSC_JBOSS_SERVER_TYPE);
ConnectionProps.setProperty(ServiceClientFactoryProperties.DSC_CREDENTIAL_USERNAME, "apink");
ConnectionProps.setProperty(ServiceClientFactoryProperties.DSC_CREDENTIAL_PASSWORD, "password");

//Create a ServiceClientFactory object
ServiceClientFactory myFactory = ServiceClientFactory.createInstance(ConnectionProps);

//Create a TaskManager object
TaskManager myTaskManager = TaskManagerClientFactory.getTaskManager(myFactory);

//Get the user identifer by calling
//a user-defined method
String userID = getUserId(myFactory);

//Forward task to another user
myTaskManager.forwardTask(17,userID);
}
catch(Exception e)
{
e.printStackTrace();
}
}

As you can see, I use the user apink ( because it's the owner of the task N°17 )

my method getUserId() :

static private String getUserId(ServiceClientFactory myFactory){
String oid = "";
try{

//Create a DirectoryManagerServiceClient object
DirectoryManagerServiceClient dirClient = new DirectoryManagerServiceClient(myFactory);

//Find a local user
PrincipalSearchFilter psf = new PrincipalSearchFilter();
psf.setUserId("tblue");
List principalList = dirClient.findPrincipals(psf);
Iterator pit = principalList.iterator();

User testUser = null;
if (pit.hasNext())
{
//Obtain the principals object identifier
testUser = (User)(pit.next());
}
oid = testUser.getOid();
}
catch(Exception e)
{
e.printStackTrace();
}

return oid;
}

I have this exception :

com.adobe.pof.POFException: No Active User in an Active Domain found for Principal ID:

If I use "administrator" instead of "apink" I have this exception

com.adobe.idp.taskmanager.dsc.client.task.TaskNotFoundException: Task: 17 was not found, or it is not in the correct state for the operation you are attempting - task not reassigned.

Anyone have an Idea ?

Thanks

Thomas