castor问题

我用castor把一对象映射成xml文件，编译通过，但是运行出现异常，请高手指教：
import java.io.*;
import org.exolab.castor.xml.*;
public class Test
{
public static void main(String[] argv) {
FlightBean bean =new FlightBean( );
bean.setCarrier( "AR ");
bean.setNumber(426);
bean.setDepartureTime( "6:23a ");
bean.setArrivalTime( "8:42a ");
try {
File file = new File( "test.xml ");
Writer writer=new FileWriter(file);
Marshaller.marshal(bean, writer);
} catch(Exception e) { }
}
}
class FlightBean implements java.io.Serializable
{
private String m_carrier;
private int m_number;
private String m_departure;
private String m_arrival;
public FlightBean( ) {m_carrier=null;m_number=0;m_departure=null;m_arrival=null;}
public void setCarrier(String carrier) { m_carrier = carrier;}
public String getCarrier() { return m_carrier; }
public void setNumber(int number) { m_number = number; }
public int getNumber() { return m_number; }
public void setDepartureTime(String time) { m_departure = time; }
public String getDepartureTime() { return m_departure; }
public void setArrivalTime(String time) { m_arrival = time; }
public String getArrivalTime() { return m_arrival; }
}
E:\ccc> javac Test.java
E:\ccc> java Test
org.xml.sax.SAXException:
unable to instantiate FlightBean; java.lang.IllegalAccessException:
Class org.exolab.castor.xml.UnmarshalHandler can not access a member of class
FlightBean with modifiers "public " at org.exolab.castor.xml.UnmarshalHandler.startElement(Unknown Source)