在用validator进行验证时，出现以下错误.急，请教各位大侠

Question

我的validation.xml文件内容如下:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE form-validation PUBLIC "-//Apache Software Foundation//DTD Commons Validator Rules Configuration 1.0//EN" "validator_1_0.dtd" >
<form-validation> <formset>
<form name="searchForm">
<field property="ssNum" depends="mask">
<arg0 key="label.search.ssnum"></arg0>
<var>
<var-name>mask</var-name>
<var-value>^\d{3}-\d{2}-\d{4}$</var-value>
</var></field>
</form>
</formset></form-validation>

Answer 1

配置文件
 <!-- ========== Plug Ins Configuration ================================= -->
     <plug-in className="org.apache.struts.validator.ValidatorPlugIn">
        <set-property property="pathnames" value="/WEB-INF/validator-rules.xml,/WEB-INF/validation.xml" />
    </plug-in>