急需高手帮忙

form：
public class IUR_Frm extends PCU_BaseFrm
{ // *************************************/
// data Definitions
// *************************************/ private static final long serialVersionUID = 6752415064805072293L; private List< ICU_MailAddrInfo > mailAddrInfo;
private String regist;


private ICU_MailAddrInfo mailTarget;
public IUR_Frm()
{
Factory factory = new Factory()
{
public Object create()
{
return new ICU_MailAddrInfo();
}
}; mailAddrInfo = ListUtils.lazyList(new ArrayList(), factory);
}
public List< ICU_MailAddrInfo > getMailAddrInfo()
{
return mailAddrInfo;
}
public void setMailAddrInfo(
List< ICU_MailAddrInfo > mailAddrInfo
)
{
this.mailAddrInfo = mailAddrInfo;
} public String getRegist()
{
return regist;
}
public void setRegist(
String regist
)
{
this.regist = regist;
}
public ICU_MailAddrInfo getMailTarget()
{
return mailTarget;
}
public void setMailTarget(
ICU_MailAddrInfo mailTarget
)
{
this.mailTarget = mailTarget;
}

}ICU_MailAddrInfo：
public class ICU_MailAddrInfo
{ // *************************************/
// data Definitions
// *************************************/
private int areaNo;
private String mailAddr;
private String sendFlag;
private String sendTestMail;
public int getAreaNo()
{
return areaNo;
}
public void setAreaNo(
int areaNo
)
{
this.areaNo = areaNo;
} public String getMailAddr()
{
return mailAddr;
}
public void setMailAddr(
String mailAddr
)
{
this.mailAddr = mailAddr;
}
public String getSendFlag()
{
return sendFlag;
}
public void setSendFlag(
String sendFlag
)
{
this.sendFlag = sendFlag;
}
public String getSendTestMail()
{
return sendTestMail;
} public void setSendTestMail(
String sendTestMail
)
{
this.sendTestMail = sendTestMail;
}
}jsp：
<html:html>
<head>

<link href="./css/style.css" rel="stylesheet" type="text/css"/>
</head><body>
<table width="100%" height="100%" cellspacing="0" cellpadding="0">
<tr valign="top">
<td>
<br>
<center>
<table>
<tr>
<td class="title">テストメール送信確認</td>
</tr>
</table>
<br>
テストメールを送信しますか？

<br>
<br>
<table>
<tr>
<form name="IUR_Frm" action="./IUR_SendTestMail.do" method="post" >
<td align="center">
<nested:root name="IUR_Frm">
<nested:nest property="mailTarget">
<nested:hidden property="mailAddr"/>
</nested:nest>
</nested:root>
<html:submit value="送信" styleClass="button1"/>
</td>
</form>
</tr>
</table>
</center>
</td>
</tr>
</table>
</body>
</html:html>
点送信出现以下问题：
javax.servlet.ServletException: BeanUtils.populate
org.apache.struts.util.RequestUtils.populate(RequestUtils.java:495)
org.apache.struts.action.RequestProcessor.processPopulate(RequestProcessor.java:816)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:203)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:169)
原因 java.lang.IllegalArgumentException: No bean specified
org.apache.commons.beanutils.PropertyUtils.getPropertyDescriptor(PropertyUtils.java:837)
org.apache.commons.beanutils.BeanUtils.setProperty(BeanUtils.java:934)
org.apache.commons.beanutils.BeanUtils.populate(BeanUtils.java:808)
org.apache.struts.util.RequestUtils.populate(RequestUtils.java:493)
org.apache.struts.action.RequestProcessor.processPopulate(RequestProcessor.java:816)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:203)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:169)根本没有去走action
如果把<nested:hidden property="mailAddr"/>
变成<nested:write property="mailAddr"/>也没有问题，只要改成具有提交功能的标签就会出现错误，小弟着急，希望高手帮忙。