Webflow: SAXParseException: cvc-complex-type.2.4.a: Invalid content was found starting with element 'set'.

SEVERE: Servlet.service() for servlet apr threw exception
org.xml.sax.SAXParseException: cvc-complex-type.2.4.a: Invalid content was found starting with element 'set'. One of '{"http://www.springframework.org/schema/webflow":attribute}' is expected.
at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:195)
at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.error(ErrorHandlerWrapper.java:131)
at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:384)
at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:318)

Dapat agak error ni sebab salah letak attribut, tapi jenuh jugak la nak cari. Hilang setengah hari.
Rupa2nya sebab ini:


<evaluate expression="studyPlanFrmService.saveStudyPlan(flowScope.studyPlanForm)" result="flowScope.studyPlanform">
<set name="flowScope.msj" value="flowScope.studyPlanForm.formMessage" ></set>
</evaluate>

<set></set> tak boleh diletak dalam <evaluate></evaluate> ???
Tak kisahlah, asal jalan kod aku.