Can't serialize org.dom4j.Document using JBoss Marshalling API java.io.NotActiveException: writeFields()

package test.t4;
import org.dom4j.Document;
public class Movie implements java.io.Serializable {

    private static final long serialVersionUID = 1L;

    private String title;
    private String director;
    private transient int code;
    private int year;
    private Document docXml;

    public Movie() {
        super();
    }

    public Movie(String title, String director, int code, int year) {
        super();
        this.title = title;
        this.director = director;
        this.code = code;
        this.year = year;
    }

    //Getters and Setters

    @Override
    public String toString() {
        return "Movie [title=" + title + ", director=" + director + ", year="
                + year + ", docXml=" + docXml + "]";
    }

}

package test.t4;

import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;
import org.jboss.marshalling.Marshaller;
import org.jboss.marshalling.MarshallerFactory;
import org.jboss.marshalling.Marshalling;
import org.jboss.marshalling.MarshallingConfiguration;
import org.jboss.marshalling.river.RiverMarshallerFactory;

public final class WriteExample {

    final static String file = "D:/TEST/serialization/jboss40.ser";

    public static void main(String[] args) {

        Document docXml = null;
        Movie mov0 = new Movie("The Hobbit: An Unexpected Journey",
                "Peter Jackson", 123456780, 2012);
        docXml = createDocument();
        mov0.setDocXml(docXml);

        Map<String, Movie> maps = new HashMap<String, Movie>();
        maps.put("Hobbit", mov0);

        System.out.println("maps : " + maps);

        goMarshall(maps);
        //serialize(maps);//When using the native Serialization Java API, the serialization works.
    }


	public static void serialize(Map<String, Movie> maps) {
		try {
			FileOutputStream fileOut = new FileOutputStream(fileJDKSerialize);
			ObjectOutputStream out = new ObjectOutputStream(fileOut);
			out.writeObject(maps);
			out.close();
			fileOut.close();
			System.out
					.printf("Serialized data is saved in " + fileJDKSerialize);
		} catch (IOException i) {
			i.printStackTrace();
		}
	}

    public static Document createDocument() {
        Document document = DocumentHelper.createDocument();
        Element starring = document.addElement("Starring");

        Element actor1 = starring.addElement("actor")
                .addAttribute("name", "Martin Freeman")
                .addAttribute("character", "Bilbo").addText("Good morning.");
        Element actor2 = starring
                .addElement("actor")
                .addAttribute("name", "Ian McKellen")
                .addAttribute("character", "Gandalf")
                .addText(
                        "What do you mean? Do you mean to wish me a good morning or do you mean that it is a good morning whether I want it or not? Or perhaps you mean to say that you feel good on this particular morning. Or are you simply stating that this is a morning to be good on? ");

        return document;
    }

    public static void goMarshall(Object obj) {
        // Get the factory for the "river" marshalling protocol
        final MarshallerFactory marshallerFactory = new RiverMarshallerFactory();

        // Create a configuration
        final MarshallingConfiguration configuration = new MarshallingConfiguration();
        // Use version 3
        configuration.setVersion(3);
        try {
            final Marshaller marshaller = marshallerFactory
                    .createMarshaller(configuration);
            final FileOutputStream os = new FileOutputStream(file);
            try {

                marshaller.start(Marshalling.createByteOutput(os));
                marshaller.writeObject(obj);
                marshaller.finish();
                os.close();
            } finally {
                // clean up stream resource
                try {
                    os.close();
                } catch (IOException e) {
                    System.err.print("Stream close failed: ");
                    e.printStackTrace();
                }
            }
        } catch (IOException e) {
            System.err.print("Marshalling failed: ");
            e.printStackTrace();
        }
    }
}