Help required in AOP Programming

I am a newbie in Spring and trying to learn. I am using the Spring in Action 3rd edition as starting point. I implemented the following example.

Knight.java
========
package com.springinaction.knights;
public abstract class Knight {
public abstract void embarkQuest() ;
}
DragonSlayingKnights.java
===================
package com.springinaction.knights;
public class DragonSlayingKnights extends Knight {
Quest quest;
public DragonSlayingKnights(Quest quest){
this.quest = quest ;
}
@Override
public void embarkQuest() {
quest.embark();
}
}
FightingKnight.java
==============
package com.springinaction.knights;
public class FightingKnight extends Knight {
Quest quest ;
public FightingKnight(Quest quest){
this.quest = quest;
}
@Override
public void embarkQuest() {
quest.embark();
}
}
Quest.java
========
package com.springinaction.knights;
public abstract class Quest {
public abstract void embark();
}
DragonSlayingQuest.java
===================
package com.springinaction.knights;
public class DragonSlayingQuest extends Quest {
@Override
public void embark() {
System.out.println("I am on a Dragon Slaying Quest");
}
}
FightingQuest.java
==============
package com.springinaction.knights;
public class FightingQuest extends Quest {
@Override
public void embark() {
System.out.println("I am on a Fighting Quest");
}
}
Minstrel.java
=========
package com.springinaction.knights;
public class Minstrel {
public void singBeforeQuest(){
System.out.println("Falala;Theknightissobrave!");
}

public void singAfterQuest(){
System.out.println("Tee heehe;Thebraveknightdidembarkonaquest!");
}
}
configuration.xml
=============
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schem...-beans-3.0.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-3.0.xsd">
<bean id="knight" class="com.springinaction.knights.DragonSlayingKni ghts">
<constructor-arg ref="quest"/>
</bean>
<bean id="quest" class="com.springinaction.knights.DragonSlayingQue st"/>
<bean id="minstrel" class="com.springinaction.knights.Minstrel"/>
<aop:config>
<aop:aspect ref="minstrel">
<aop:pointcut id="embark" expression="execution(* com.springinaction.knights.Knight.embarkQuest(..)) " />
<aop:before pointcut-ref="embark" method="singBeforeQuest"/>
<aop:after pointcut-ref="embark" method="singAfterQuest"/>
</aop:aspect>
</aop:config>
</beans>

Test File - TestKnights.java
=====================
package com.test.spring;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlAp plicationContext;
import com.springinaction.knights.Knight;

public class TestKnights {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("configuration.xml" );
Knight knight = (Knight) context.getBean("knight");
knight.embarkQuest();
}
}

When I execute the TestKnights.java, I get the following error:

Nov 5, 2011 2:31:09 AM org.springframework.context.support.AbstractApplic ationContext prepareRefresh
INFO: Refreshing org.springframework.context.support.ClassPathXmlAp plicationContext@1f5a3d6b: startup date [Sat Nov 05 02:31:09 PDT 2011]; root of context hierarchy
Nov 5, 2011 2:31:09 AM org.springframework.beans.factory.xml.XmlBeanDefin itionReader loadBeanDefinitions
INFO: Loading XML bean definitions from class path resource [configuration.xml]
Nov 5, 2011 2:31:09 AM org.springframework.beans.factory.support.DefaultL istableBeanFactory preInstantiateSingletons
INFO: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultL istableBeanFactory@6da28362: defining beans [knight,quest,minstrel,org.springframework.aop.conf ig.internalAutoProxyCreator,org.springframework.ao p.aspectj.AspectJPointcutAdvisor#0,org.springframe work.aop.aspectj.AspectJPointcutAdvisor#1,embark]; root of factory hierarchy
Nov 5, 2011 2:31:09 AM org.springframework.beans.factory.support.DefaultS ingletonBeanRegistry destroySingletons
INFO: Destroying singletons in org.springframework.beans.factory.support.DefaultL istableBeanFactory@6da28362: defining beans [knight,quest,minstrel,org.springframework.aop.conf ig.internalAutoProxyCreator,org.springframework.ao p.aspectj.AspectJPointcutAdvisor#0,org.springframe work.aop.aspectj.AspectJPointcutAdvisor#1,embark]; root of factory hierarchy
Exception in thread "main" org.springframework.beans.factory.BeanCreationExce ption: Error creating bean with name 'knight' defined in class path resource [configuration.xml]: BeanPostProcessor before instantiation of bean failed; nested exception is org.springframework.beans.factory.BeanCreationExce ption: Error creating bean with name 'org.springframework.aop.aspectj.AspectJPointcutAd visor#0': Cannot create inner bean '(inner bean)' of type [org.springframework.aop.aspectj.AspectJMethodBefor eAdvice] while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationExce ption: Error creating bean with name '(inner bean)': Cannot resolve reference to bean 'embark' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationExce ption: Error creating bean with name 'embark': Instantiation of bean failed; nested exception is java.lang.NoClassDefFoundError: org/aspectj/weaver/reflect/ReflectionWorld$ReflectionWorldException
.........

The complete error is available in the attached file.

I am not able to fix this error. Can somebody help me? Thanks in advance.