I try spring-modules-validation-bean-samples-src sample program from the spring-modules-0.9-with-dependencies.zip file with Spring 2.5.6 and Eclipse for RCP/Plug-in Developers (Build id: 20100218-1602).

validator-servlet.xml is:
Code:
<?xml version="1.0" encoding="ISO-8859-1"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:vld="http://www.springmodules.org/validation/bean/validator"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
                        http://www.springmodules.org/validation/bean/validator http://www.springmodules.org/validation/bean/validator.xsd">

    <!--================================= Message sources ======================================-->

    <bean id="messageSource" class="org.springframework.context.support.ResourceBundleMessageSource">
        <property name="basenames" value="messages,domain-messages"/>
	</bean>



    <!--================================== View Resolvers =======================================-->

	<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<property name="viewClass" value="org.springframework.web.servlet.view.JstlView" />
		<property name="prefix" value="WEB-INF/jsp/" />
		<property name="suffix" value=".jsp" />
	</bean>



    <!--================================ Handler mappings =====================================-->

	<bean id="handlerMapping" class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/>

    <!--=================================== Controllers ========================================-->

    <bean name="/person.html" class="org.springmodules.samples.validation.bean.web.PersonFormController">
		<property name="formView" value="person"/>
        <property name="successView" value="redirect:/success.html"/>
        <property name="validator" ref="beanValidator"/>
        <property name="commandName" value="person"/>
        <property name="commandClass" value="org.springmodules.samples.validation.bean.web.PersonData"/>
    </bean>

    <bean name="/success.html" class="org.springframework.web.servlet.mvc.UrlFilenameViewController"/>

    <!--=================================== Bean Validator =====================================-->

    <vld:annotation-based-validator id="beanValidator"/>

    <!--
        comment the annotation-based-validator above and uncomment this element
        to check out the xml based validation. You'll find validation.xml under
        the src/etc/resources directory of this project.
    -->
    <!--<vld:xml-based-validator id="beanValidator">-->
        <!--<vld:resource location="classpath:validation.xml"/>-->
    <!--</vld:xml-based-validator>-->

</beans>
The Eclipse console error is:
10:29:41,546 ERROR org.springframework.osgi.web.context.support.OsgiB undleXmlWebApplicationContext:152 - Refresh error
org.springframework.beans.factory.parsing.BeanDefi nitionParsingException: Configuration problem: Unable to locate Spring NamespaceHandler for XML schema namespace [http://www.springmodules.org/validation/bean/validator]
Offending resource: URL [bundleentry://9.fwk13665843/WEB-INF/validator-servlet.xml]
at org.springframework.beans.factory.parsing.FailFast ProblemReporter.error(FailFastProblemReporter.java :68)