Applet + BufferedImage + RMI

package digitalizacao;
 
 import java.awt.image.BufferedImage;
 import java.awt.image.ColorModel;
 import java.awt.image.IndexColorModel;
 import java.awt.image.WritableRaster;
 import java.io.Serializable;
 import java.util.Hashtable;
 
 public class ImagemDigitalizacao extends BufferedImage implements Serializable
 {
 	public ImagemDigitalizacao(ColorModel arg0, WritableRaster arg1, boolean arg2, Hashtable<?, ?> arg3)
 	{
 		super(arg0, arg1, arg2, arg3);
 	}
 
 	public ImagemDigitalizacao(int arg0, int arg1, int arg2, IndexColorModel arg3)
 	{
 		super(arg0, arg1, arg2, arg3);
 	}
 
 	public ImagemDigitalizacao(int arg0, int arg1, int arg2)
 	{
 		super(arg0, arg1, arg2);
 	}
 	
 	public static ImagemDigitalizacao getImagemDigitalizacao(BufferedImage image)
 	{
 		Hashtable hashtable = null;
 		String[] propriedades = image.getPropertyNames();
 		if(propriedades != null)
 		{
 			hashtable =  new Hashtable(propriedades.length);
 			for(int i = 0; i < propriedades.length; i++)
 			{
 				hashtable.put(propriedades[i],image.getProperty(propriedades[i]));
 			}
 		}
 		else
 			hashtable = new Hashtable();
 		return new ImagemDigitalizacao(image.getColorModel(), image.getRaster(), image.isAlphaPremultiplied(),hashtable);
 	}
 }

java.rmi.ServerException: RemoteException occurred in server thread; nested exception is: 
 	java.rmi.UnmarshalException: error unmarshalling arguments; nested exception is: 
 	java.io.InvalidClassException: digitalizacao.ImagemDigitalizacao; no valid constructor
 	at sun.rmi.server.UnicastServerRef.dispatch(Unknown Source)
 	at sun.rmi.transport.Transport$1.run(Unknown Source)
 	at java.security.AccessController.doPrivileged(Native Method)
 	at sun.rmi.transport.Transport.serviceCall(Unknown Source)
 	at sun.rmi.transport.tcp.TCPTransport.handleMessages(Unknown Source)
 	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(Unknown Source)
 	at java.lang.Thread.run(Unknown Source)
 	at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(Unknown Source)
 	at sun.rmi.transport.StreamRemoteCall.executeCall(Unknown Source)
 	at sun.rmi.server.UnicastRef.invoke(Unknown Source)
 	at java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(Unknown Source)
 	at java.rmi.server.RemoteObjectInvocationHandler.invoke(Unknown Source)
 	at $Proxy0.salvaDocumento(Unknown Source)
 	at digitalizacao.Indexar$4.actionPerformed(Indexar.java:542)
 	at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
 	at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
 	at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
 	at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
 	at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
 	at java.awt.Component.processMouseEvent(Unknown Source)
 	at javax.swing.JComponent.processMouseEvent(Unknown Source)
 	at java.awt.Component.processEvent(Unknown Source)
 	at java.awt.Container.processEvent(Unknown Source)
 	at java.awt.Component.dispatchEventImpl(Unknown Source)
 	at java.awt.Container.dispatchEventImpl(Unknown Source)
 	at java.awt.Component.dispatchEvent(Unknown Source)
 	at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
 	at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
 	at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
 	at java.awt.Container.dispatchEventImpl(Unknown Source)
 	at java.awt.Window.dispatchEventImpl(Unknown Source)
 	at java.awt.Component.dispatchEvent(Unknown Source)
 	at java.awt.EventQueue.dispatchEvent(Unknown Source)
 	at java.awt.EventDispatchThread.pumpOneEventForHierarchy(Unknown Source)
 	at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
 	at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
 	at java.awt.Dialog$1.run(Unknown Source)
 	at java.awt.Dialog$2.run(Unknown Source)
 	at java.security.AccessController.doPrivileged(Native Method)
 	at java.awt.Dialog.show(Unknown Source)
 	at digitalizacao.Indexar.initialize(Indexar.java:100)
 	at digitalizacao.Indexar.<init>(Indexar.java:87)
 	at digitalizacao.AppletDigitalizacao$2.actionPerformed(AppletDigitalizacao.java:169)
 	at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
 	at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
 	at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
 	at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
 	at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
 	at java.awt.Component.processMouseEvent(Unknown Source)
 	at javax.swing.JComponent.processMouseEvent(Unknown Source)
 	at java.awt.Component.processEvent(Unknown Source)
 	at java.awt.Container.processEvent(Unknown Source)
 	at java.awt.Component.dispatchEventImpl(Unknown Source)
 	at java.awt.Container.dispatchEventImpl(Unknown Source)
 	at java.awt.Component.dispatchEvent(Unknown Source)
 	at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
 	at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
 	at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
 	at java.awt.Container.dispatchEventImpl(Unknown Source)
 	at java.awt.Component.dispatchEvent(Unknown Source)
 	at java.awt.EventQueue.dispatchEvent(Unknown Source)
 	at java.awt.EventDispatchThread.pumpOneEventForHierarchy(Unknown Source)
 	at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
 	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
 	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
 	at java.awt.EventDispatchThread.run(Unknown Source)
 Caused by: java.rmi.UnmarshalException: error unmarshalling arguments; nested exception is: 
 	java.io.InvalidClassException: digitalizacao.ImagemDigitalizacao; no valid constructor
 	at sun.rmi.server.UnicastServerRef.dispatch(Unknown Source)
 	at sun.rmi.transport.Transport$1.run(Unknown Source)
 	at java.security.AccessController.doPrivileged(Native Method)
 	at sun.rmi.transport.Transport.serviceCall(Unknown Source)
 	at sun.rmi.transport.tcp.TCPTransport.handleMessages(Unknown Source)
 	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(Unknown Source)
 	at java.lang.Thread.run(Unknown Source)
 Caused by: java.io.InvalidClassException: digitalizacao.ImagemDigitalizacao; no valid constructor
 	at java.io.ObjectStreamClass.<init>(Unknown Source)
 	at java.io.ObjectStreamClass.lookup(Unknown Source)
 	at java.io.ObjectStreamClass.initNonProxy(Unknown Source)
 	at java.io.ObjectInputStream.readNonProxyDesc(Unknown Source)
 	at java.io.ObjectInputStream.readClassDesc(Unknown Source)
 	at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source)
 	at java.io.ObjectInputStream.readObject0(Unknown Source)
 	at java.io.ObjectInputStream.readObject(Unknown Source)
 	at java.util.ArrayList.readObject(Unknown Source)
 	at sun.reflect.GeneratedMethodAccessor24.invoke(Unknown Source)
 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
 	at java.lang.reflect.Method.invoke(Unknown Source)
 	at java.io.ObjectStreamClass.invokeReadObject(Unknown Source)
 	at java.io.ObjectInputStream.readSerialData(Unknown Source)
 	at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source)
 	at java.io.ObjectInputStream.readObject0(Unknown Source)
 	at java.io.ObjectInputStream.readObject(Unknown Source)
 	at sun.rmi.server.UnicastRef.unmarshalValue(Unknown Source)
 	... 7 more