大家帮忙看看是哪的问题，我实在没办法了，帮帮忙！！！

我的JSP页面出错如下：
org.apache.jasper.JasperException: Unable to compile class for JSP

An error occurred at line: 21 in the jsp file: /try.jsp

Generated servlet error:
[javac] Compiling 1 source file

F:\tomcat\jakarta\work\Catalina\localhost\mywork\org\apache\jsp\try_jsp.java:72: cannot access tree.GuardForceBean



An error occurred at line: 21 in the jsp file: /try.jsp

Generated servlet error:
bad class file: F:\tomcat\jakarta\webapps\mywork\WEB-INF\classes\tree\GuardForceBean.class
class file contains wrong class: GuardForceBean
Please remove or make sure it appears in the correct subdirectory of the classpath.
GuardForceBean read = (GuardForceBean)unmarshaller.unmarshal(reader);
^
1 error


我的BEAN 都放在F:\tomcat\jakarta\webapps\mywork\WEB-INF\classes\tree下，有GuardForceBean.class,JSP代码中也包括<%@ page import="tree.*" %>，我不知道是哪出了错，是设置问题还是代码问题呢？这个问题搞了好久都没搞出来，我又很菜，大家帮帮忙啊！！！！谢谢了