Would anybody please help me on my issue? thanks your advice in advance!
Followed the 'duke bank' example in Startguide, I write a simple example. which only has one EJB and a client. By 'ant -f jboss-build.xml deploy', I have deployed it to the Jboss 4.0.2 (default server), and it is said it has been success deployed and started. However, when I run the client by 'ant -f jboss-build.xml run-client', I got such errors:

[java] Caught an unexpected exception!
[java] java.lang.SecurityException: Unable to locate a login configuration
[java] at com.sun.security.auth.login.ConfigFile.<init>(ConfigFile.java
:97)
[java] at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native
Method)
[java] at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeC
onstructorAccessorImpl.java:39)
[java] at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Del
egatingConstructorAccessorImpl.java:27)
[java] at java.lang.reflect.Constructor.newInstance(Constructor.java:27
4)
[java] at java.lang.Class.newInstance0(Class.java:308)
[java] at java.lang.Class.newInstance(Class.java:261)
[java] at javax.security.auth.login.Configuration$3.run(Configuration.j
ava:221)
[java] at java.security.AccessController.doPrivileged(Native Method)
[java] at javax.security.auth.login.Configuration.getConfiguration(Conf
iguration.java:215)
[java] at javax.security.auth.login.LoginContext$1.run(LoginContext.jav
a:170)
[java] at java.security.AccessController.doPrivileged(Native Method)
[java] at javax.security.auth.login.LoginContext.init(LoginContext.java
:167)
[java] at javax.security.auth.login.LoginContext.<init>(LoginContext.ja
va:404)
[java] at org.jboss.security.jndi.LoginInitialContextFactory.getInitial
Context(LoginInitialContextFactory.java:69)
[java] at javax.naming.spi.NamingManager.getInitialContext(NamingManage
r.java:662)
[java] at javax.naming.InitialContext.getDefaultInitCtx(InitialContext.
java:243)
[java] at javax.naming.InitialContext.init(InitialContext.java:219)
[java] at javax.naming.InitialContext.<init>(InitialContext.java:175)
[java] at GoldClient.main(GoldClient.java:14)
[java] Caused by: java.io.IOException: Unable to locate a login configurati
on
[java] at com.sun.security.auth.login.ConfigFile.init(ConfigFile.java:2
06)
[java] at com.sun.security.auth.login.ConfigFile.<init>(ConfigFile.java
:95)
[java] ... 19 more

I don't know what is wrong with it, actually I have deployed it by 'sun deploytool' to the sun j2ee sdk 1.4 default server, and everything work perfect. So I guess the problem is caused by the JNDI or the deployment descriptor of my client. Here I give all the info:

jboss-build.xml:

<project name="jboss-MiningGold" default="all" basedir=".">
 <property file="./jboss-build.properties"/>

 <property name="lib.dir" value="../libs"/>
 <property name="src.dir" value="${basedir}/src"/>
 <property name="build.dir" value="${basedir}/build"/>



 <!-- The classpath for running the client -->
 <path id="client.classpath">
 <pathelement location="${build.dir}"/>
 <fileset dir="${jboss.home}/client">
 <include name="**/*.jar"/>
 </fileset>
 </path>

 <!-- The build classpath -->
 <path id="axis.classpath">
 <pathelement location="${build.dir}"/>
 <fileset dir="/Users/orb/Desktop/axis-1_1/lib">
 <include name="*.jar"/>
 </fileset>
 <fileset dir="${jboss.server}/lib/">
 <include name="javax.servlet*.jar"/>
 </fileset>
 </path>


 <!-- The build classpath -->
 <path id="build.classpath">
 <path refid="client.classpath"/>
 <fileset dir="${jboss.server}/lib/">
 <include name="javax.servlet*.jar"/>
 </fileset>
 <!-- for java2wsdl -->
 <fileset dir="${jboss.server}/deploy/jboss-ws4ee.sar/">
 <include name="*.jar"/>
 </fileset>
 </path>

 <!-- =================================================================== -->
 <!-- Initialises the build. -->
 <!-- =================================================================== -->
 <target name="prepare">
 <mkdir dir="${build.dir}"/>
 </target>

 <!-- ================================================================ -->
 <!-- Compiles the source code -->
 <!-- ================================================================ -->
 <target name="compile" depends="prepare">
 <javac destdir="${build.dir}" classpathref="build.classpath"
 debug="on">
 <src path="${src.dir}"/>
 </javac>
 </target>

 <target name="package-ejb" depends="compile">
 <mkdir dir="jar" />
 <delete file="jar/gold-ejb.jar"/>

 <jar jarfile="jar/gold-ejb.jar">
 <metainf dir="dd/ejb" includes="**/*.xml" />

 <fileset dir="${build.dir}">
 <include name="gold/**"/>
 </fileset>
 </jar>
 </target>

 <target name="package-client" depends="compile">
 <mkdir dir="jar" />
 <delete file="jar/app-client.jar"/>

 <jar jarfile="jar/app-client.jar">
 <metainf dir="dd/client" includes="*.xml"/>
 <fileset dir="${build.dir}">
 <include name="GoldClient.class"/>
 <include name="gold/Gold.class"/>
 <include name="gold/GoldHome.class"/>
 </fileset>
 <fileset dir="dd/client">
 <include name="jndi.properties"/>
 </fileset>
 </jar>
 </target>

 <!-- Creates an ear file containing the ejb jars and the web client war. -->
 <target name="assemble-app">
 <delete file="jar/MiningGold.ear"/>
 <ear destfile="jar/MiningGold.ear" appxml="dd/application.xml">
 <fileset dir="jar" includes="*-ejb.jar,app-client.jar"/>
 </ear>
 </target>

 <!-- Deploys the EAR file by copying it to the JBoss deploy directory. -->
 <target name="deploy" depends="assemble-app">
 <copy file="jar/MiningGold.ear" todir="${jboss.server}/deploy"/>
 </target>

 <!-- Run the standalone client -->
 <target name="run-client">
 <echo>${java.class.path}</echo>
 <java classname="GoldClient" fork="yes">
 <classpath>
 <pathelement path="jar/app-client.jar"/>
 <path refid="client.classpath"/>
 <pathelement path="${java.class.path}"/>
 </classpath>
 </java>
 </target>


 <target name="clean">
 <delete dir="${build.dir}" />
 <mkdir dir="${build.dir}" />

 </target>


 <target name="all" depends="compile,package-ejb,package-client,assemble-app,deploy" />

</project>

EJB deployment desriptor:
ejb-jar.xml:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE ejb-jar PUBLIC "-//Sun Microsystems, Inc.//DTD Enterprise JavaBeans 2.0//EN" "http://java.sun.com/dtd/ejb-jar_2_0.dtd">
<ejb-jar >

 <description><![CDATA[No Description.]]></description>
 <display-name>Generated by XDoclet</display-name>

 <enterprise-beans>

 <!-- Session Beans -->
 <session >
 <description><![CDATA[Description for Gold]]></description>
 <display-name>Name for Gold</display-name>

 <ejb-name>Gold</ejb-name>

 <home>gold.GoldHome</home>
 <remote>gold.Gold</remote>
 <ejb-class>gold.GoldBean</ejb-class>
 <session-type>Stateful</session-type>
 <transaction-type>Container</transaction-type>

 </session>


 </enterprise-beans>

 <assembly-descriptor >
 </assembly-descriptor>

</ejb-jar>

jboss.xml:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE jboss PUBLIC "-//JBoss//DTD JBOSS 3.2//EN" "http://www.jboss.org/j2ee/dtd/jboss_3_2.dtd">

<jboss>

 <enterprise-beans>

 <session>
 <ejb-name>Gold</ejb-name>
 <jndi-name>ejb/Gold</jndi-name>

 <method-attributes>
 </method-attributes>
 </session>

 </enterprise-beans>

 <resource-managers>
 </resource-managers>

</jboss>

For client:
jboss-client.xml:

<jboss-client>
 <jndi-name>Gold-client</jndi-name>

 <ejb-ref>
 <ejb-ref-name>ejb/SimpleGold</ejb-ref-name>
 <jndi-name>ejb/Gold</jndi-name>
 </ejb-ref>

</jboss-client>

application-client.xml:

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE application-client PUBLIC
 '-//Sun Microsystems, Inc.//DTD J2EE Application Client 1.3//EN'
 'http://java.sun.com/dtd/application-client_1_3.dtd'>
<application-client>
 <display-name>GoldClient</display-name>

 <ejb-ref>
 <ejb-ref-name>ejb/SimpleGold</ejb-ref-name>
 <ejb-ref-type>Session</ejb-ref-type>
 <home>GoldHome</home>
 <remote>Gold</remote>
 </ejb-ref>
</application-client>

jndi.properties

java.naming.factory.initial=org.jboss.security.jndi.LoginInitialContextFactory
#org.jnp.interfaces.NamingContextFactory
java.naming.provider.url=jnp://localhost:1099
java.naming.factory.url.pkgs=org.jboss.naming.client
java.naming.security.principal=200
java.naming.security.credentials=j2ee
java.naming.security.protocol=client-login
j2ee.clientName=Gold-client

*******************************************************************************************
The java files:
GoldBean.java:

package gold;

import java.rmi.RemoteException;
import javax.ejb.SessionBean;
import javax.ejb.SessionContext;
import java.math.*;


public class GoldBean implements SessionBean {
 BigDecimal Increase_Rate = new BigDecimal("1.0000");

 public GoldBean() {
 }

 public BigDecimal MiningGold(BigDecimal dollars, String userName) {
 BigDecimal result = dollars.add(Increase_Rate);
 System.out.print(userName + " has earned: ");
 System.out.println(result);
 return result;
 }

 public void ejbCreate() {
 }

 public void ejbRemove() {
 }

 public void ejbActivate() {
 }

 public void ejbPassivate() {
 }

 public void setSessionContext(SessionContext sc) {
 }
}

Gold.java:

package gold;

import javax.ejb.EJBObject;
import java.rmi.RemoteException;
import java.math.*;

public interface Gold extends EJBObject {
 public BigDecimal MiningGold(BigDecimal dollars, String userName) throws RemoteException;
}

GoldHome.java:

package gold;

import java.rmi.RemoteException;
import javax.ejb.CreateException;
import javax.ejb.EJBHome;


public interface GoldHome extends EJBHome {
 Gold create() throws RemoteException, CreateException;
}

GoldClient.java:

import gold.Gold;
import gold.GoldHome;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.rmi.PortableRemoteObject;
import java.math.BigDecimal;
import java.io.*;


public class GoldClient {
 public static void main(String[] args) {
 try {
 Context initial = new InitialContext();
 Context myEnv = (Context) initial.lookup("java:comp/env");
 Object objref = myEnv.lookup("ejb/SimpleGold");

 GoldHome home =
 (GoldHome) PortableRemoteObject.narrow(objref,
 GoldHome.class);

 Gold FindGold = home.create();

 BigDecimal param = new BigDecimal("0.00");
 BigDecimal amount = new BigDecimal("0.00");

 System.out.print("Enter the name of your company: ");
 BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
 String userName = null;
 try {
 userName = br.readLine();
 } catch (IOException ioe) {
 System.out.println("IO error trying to read your name!");
 System.exit(1);
 }


 for (int i=0; i<5000000; i++) {
 if (i%200==0){
 amount = FindGold.MiningGold(param, userName);
 param = amount;
 System.out.print(userName + " has earned: ");
 System.out.println(amount);
 }
 }


 System.exit(0);
 } catch (Exception ex) {
 System.err.println("Caught an unexpected exception!");
 ex.printStackTrace();
 }
 }
}