I am writing a simple spring mvc login form example. I am getting below error in netbeans

  05-Jun-2014 02:11:51.055 SEVERE [http-nio-8084-exec-1] org.apache.catalina.core.StandardContext.listenerStart Exception sending context initialized event to listener instance of class org.springframework.web.context.ContextLoaderListener
  org.springframework.beans.factory.BeanDefinitionStoreException: Unexpected exception parsing XML document from ServletContext resource [/WEB-INF/SpringSecurity.xml]; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [org.springframework.security.config.SecurityNamespaceHandler]: Constructor threw exception; nested exception is java.lang.NoClassDefFoundError: org/springframework/security/core/SpringSecurityCoreVersion
  at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.doLoadBeanDefinitions(XmlBeanDefinitionReader.java:413)
  at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:335)
  at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:303)
  at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:180)
  at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:216)
  at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:187)
  at org.springframework.web.context.support.XmlWebApplicationContext.loadBeanDefinitions(XmlWebApplicationContext.java:125)
  at org.springframework.web.context.support.XmlWebApplicationContext.loadBeanDefinitions(XmlWebApplicationContext.java:94)
  at org.springframework.context.support.AbstractRefreshableApplicationContext.refreshBeanFactory(AbstractRefreshableApplicationContext.java:129)
  at org.springframework.context.support.AbstractApplicationContext.obtainFreshBeanFactory(AbstractApplicationContext.java:540)
  at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:454)
  at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:403)
  at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:306)
  at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:106)
  at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4738)
  at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5158)
  at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
  at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:726)
  at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:702)
  at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:697)
  at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:579)
  at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:455)
  at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1554)
  at sun.reflect.GeneratedMethodAccessor53.invoke(Unknown Source)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  at java.lang.reflect.Method.invoke(Method.java:606)
  at org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:300)
  at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)
  at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
  at org.apache.catalina.manager.ManagerServlet.check(ManagerServlet.java:1428)
  at org.apache.catalina.manager.ManagerServlet.deploy(ManagerServlet.java:885)
  at org.apache.catalina.manager.ManagerServlet.doGet(ManagerServlet.java:343)
  at javax.servlet.http.HttpServlet.service(HttpServlet.java:618)
  at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:301)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
  at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
  at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
  at org.apache.catalina.filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:108)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
  at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
  at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
  at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:615)
  at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:136)
  at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:74)
  at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
  at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
  at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:516)
  at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1015)
  at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:652)
  at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:222)
  at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1575)
  at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1533)
  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
  at java.lang.Thread.run(Thread.java:744)
Caused by: org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [org.springframework.security.config.SecurityNamespaceHandler]: Constructor threw exception; nested exception is java.lang.NoClassDefFoundError: org/springframework/security/core/SpringSecurityCoreVersion
  at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:164)
  at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:105)
  at org.springframework.beans.factory.xml.DefaultNamespaceHandlerResolver.resolve(DefaultNamespaceHandlerResolver.java:130)
  at org.springframework.beans.factory.xml.BeanDefinitionParserDelegate.parseCustomElement(BeanDefinitionParserDelegate.java:1419)
  at org.springframework.beans.factory.xml.BeanDefinitionParserDelegate.parseCustomElement(BeanDefinitionParserDelegate.java:1414)
  at org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader.parseBeanDefinitions(DefaultBeanDefinitionDocumentReader.java:187)
  at org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader.doRegisterBeanDefinitions(DefaultBeanDefinitionDocumentReader.java:141)
  at org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader.registerBeanDefinitions(DefaultBeanDefinitionDocumentReader.java:110)
  at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.registerBeanDefinitions(XmlBeanDefinitionReader.java:508)
  at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.doLoadBeanDefinitions(XmlBeanDefinitionReader.java:391)
  ... 60 more
Caused by: java.lang.NoClassDefFoundError: org/springframework/security/core/SpringSecurityCoreVersion
  at org.springframework.security.config.SecurityNamespaceHandler.<init>(SecurityNamespaceHandler.java:65)
  at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
  at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
  at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
  at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
  at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:148)
  ... 69 more
Caused by: java.lang.ClassNotFoundException: org.springframework.security.core.SpringSecurityCoreVersion
  at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1284)
  at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1132)
  ... 75 more

I am using spring 3.2.7. It was not having spring security jar. So I got it downloaded using maven. It's version is 3.2.4. What is this error? There's no error in code. What must have gone wrong? For last 3 hours I have been trying to run a simple example, but totally hammered by this error. Please help