Struts中JSP提交Action时出现错误，请各位达人帮忙~~

JBuilder下错误：
StandardWrapperValve[action]: Servlet.service() for servlet action threw exception
javax.servlet.ServletException: BeanUtils.populate
页面错误：
javax.servlet.ServletException: BeanUtils.populate
java.lang.IllegalArgumentException: No bean specified在Action里第一行加了断点但根本没走，请教我哪个地方错误了，先谢谢各位了
问题解决马上给分~