Ajuda com RMI

import java.io.Serializable;
import java.util.HashMap;

/**
 *  Esta interface deve ser implementada pelos DAOs das classes
 *  */
public interface Dao extends Serializable{


    public boolean insert(Object o);

    public boolean update(Object o);

    public boolean delete(Object o);

    public Object getThis(int id);

    public HashMap<String,Object> getAll();

    public HashMap<String,Object> getWhere(String field,String operator,String value);

    public HashMap<String,Object> query(String query);

}

import java.rmi.Remote;
import java.rmi.RemoteException;

/**
 *
 * Definição da Interface Remota, que executará os métodos de uma classe, que implemente a interface Dao, no servidor
 */
public interface  IDataBaseRequest extends Remote{


    public boolean executeInsert(Dao dao,Object o) throws RemoteException;

    public boolean executeUpdate(Dao dao,Object o) throws RemoteException;

    ..... outros métodos que executem as ações de um objeto que impelente Dao

}

/*
* Classe de implementação da interface remota
*/
public class DataBaseRequest extends UnicastRemoteObject implements IDataBaseRequest {

    public DataBaseRequest() throws RemoteException {
        super();
    }

    public boolean executeInsert(Dao dao, Object o) throws RemoteException;
        return dao.insert(o);
    }

    public boolean executeUpdate(Dao dao, Object o) throws RemoteException;
        return dao.update(o);
    }

    public static void main(String[] args) {
        if (System.getSecurityManager() == null) {
            System.setSecurityManager(new RMISecurityManager());
        }
        String name = "//localhost/DataBaseRequest";
        try {
            DataBaseRequest dbr = new DataBaseRequest();
            Naming.rebind(name, dbr);
            System.out.println("ok");
        } catch (Exception e) {
            System.err.println("erro" + e.getMessage());
            e.printStackTrace();
        }
    }
}