初学struts的一个小问题

我用的是struts.1.3.10:程序和运行时出现的错误如下:麻烦有谁知道的告诉一下,谢谢!!//这是登录页面
<%@ page language="java" import="java.util.*" pageEncoding="gb2312"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<%@ taglib uri="/struts-tags" prefix="html" %>
<html>
   <head>
   <title>这是我的STRUTS登陆首页</title></head>
   <body>
      <html:form 
       action="/Loginaction.do" 
       method="post">
      <table border="0">
      <tr>
      <td>用户名</td>
      <td><html:text property="username"/></td>
      </tr>
      <tr>
      <td>密码</td>
      <td><html:password property="password"></html:password>
      </td>
      </tr>
      <tr colspane="2" align="center" >
      <td><html:submit value="登录"></html:submit>
      </td>
      </tr>
      </table>
    </html:form>
   </body>
</html>//登录成功后的页面
<%@ page contentType="text/html;charset=GB2312" %>
<%@ taglib uri="/WEB-INF/tlds/struts-html.tld" prefix="html"%>
<html:html>
  <head><title>登录成功页面</title></head>
 <body>
   <table align="center" border="0">
    <tr align="center"><td>
     系统登录成功！登录的用户名为：<%=request.getParameter("username")%>
    </td></tr>
   </table>
  </body>
 </html:html>//action
package form;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionErrors;
import org.apache.struts.action.ActionErrors;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.*;
/**
 * @作者:邓子云
 *控制器类
 */
public class Loginaction extends Action{
    /**
     * 在此方法中处理HTTP请求数据，并作响应
     */
    public ActionForward execute(ActionMapping mapping, ActionForm form,
            HttpServletRequest request, HttpServletResponse response) throws Exception {
        ActionErrors errors=new ActionErrors();
        String username=(String)((Loginform)form).getUsername();
        String password=(String)((Loginform)form).getPassword();
        //------用户名和密码校验------
        //此处仅作简单的校验，实际工程中一般从数据库表中作SQL查询来校验
        if(!username.equalsIgnoreCase("dengjiarong")){
            errors.add("username",new ActionMessage("login.usernamenotrue"));
            saveErrors(request,errors);
            return(new ActionForward(mapping.findForward("failure")));
        }
        if(!password.equalsIgnoreCase("123")){
           errors.add("password",new ActionMessage("login.passwordnotrue"));
            saveErrors(request,errors);
            return(new ActionForward(mapping.findForward("failure")));
        }
        //------业务逻辑代码------
        //数据检验通过后，可作业务逻辑处理，常见的操作有：记录日志、操作数据库等
        request.removeAttribute(mapping.getAttribute());//删除formBean
        return mapping.findForward("success");  
    }
}//actionfrom
package form;
import javax.servlet.http.HttpServletRequest;import org.apache.struts.action.ActionErrors;
import org.apache.struts.action.ActionErrors;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.ActionMessage;;
/**
 * @作者:邓子云
 * 登录表单类
 */
public class Loginform extends ActionForm{
    private String username=null;
    private String password=null;
    /**
     * 重置所有属性的值
     */
    public void reset(ActionMapping mapping, HttpServletRequest request) {
        this.username=null;
        this.password=null;
    }
    /**
     * 验证属性的值
     */
    public ActionErrors validate(ActionMapping mapping, HttpServletRequest request) {
        ActionErrors errors=new ActionErrors();
        if(username==null||username.length()<1)
            errors.add("username",new ActionMessage("login.usernamenull"));
        if(password==null||password.length()<1)
            errors.add("password",new ActionMessage("login.passwordnull"));
        return errors;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
}//web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<servlet>
<servlet-name>action</servlet-name>
<servlet-class>
org.apache.struts.action.ActionServlet
</servlet-class>
<init-param>
<param-name>config</param-name>
<param-value>/WEB-INF/struts-config.xml</param-value>
</init-param>
<load-on-startup>2</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>action</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>login.jsp</welcome-file>
</welcome-file-list>
<jsp-config>
<taglib>
<taglib-uri>/struts-tags</taglib-uri>
<taglib-location>/WEB-INF/tlds/struts-html.tld</taglib-location>
</taglib>
</jsp-config>
</web-app>
//struts-config.xml
<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE struts-config PUBLIC       "-//Apache Software Foundation//DTD Struts Configuration 1.3//EN"       "http://struts.apache.org/dtds/struts-config_1_3.dtd"><struts-config>
  <form-beans>
    <form-bean name="Loginform" type="form.Loginform"/>
  </form-beans>
  <action-mappings>
    <action path="/Loginaction"
     type="form.Loginaction"
     name="Loginform"
     scope="request" validate="true"
     input="/login.jsp">
     <forward name="failure" path="/login.jsp"/>
     <forward name="success" path="/success.jsp"></forward>
     </action>
  </action-mappings>
  <message-resources parameter="login_zh"/>
</struts-config>//出现的问题
The server encountered an internal error () that prevented it from fulfilling this request.exception org.apache.jasper.JasperException: Exception in JSP: /login.jsp:85:    <head>
6:    <title>这是我的STRUTS登陆首页</title></head>
7:    <body>
8:       <html:form 
9:        action="/Loginaction.do" 
10:        method="post">
11:       <table border="0">
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:451)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:355)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
root cause javax.servlet.ServletException
org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:841)
org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:774)
org.apache.jsp.login_jsp._jspService(login_jsp.java:86)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
root cause java.lang.NoClassDefFoundError
sun.reflect.GeneratedConstructorAccessor11.newInstance(Unknown Source)
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
java.lang.reflect.Constructor.newInstance(Constructor.java:494)
java.lang.Class.newInstance0(Class.java:350)
java.lang.Class.newInstance(Class.java:303)
org.apache.jasper.runtime.TagHandlerPool.get(TagHandlerPool.java:117)
org.apache.jsp.login_jsp._jspx_meth_html_005fform_005f0(login_jsp.java:98)
org.apache.jsp.login_jsp._jspService(login_jsp.java:75)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)