使用spring.net框架配置事务

<object id="MyOperate" type="Spring.Aop.Support.SdkRegularExpressionMethodPointcut, Spring.Aop">
    <property name="patterns">
      <list>
        <value>.*Transaction</value>
      </list>
    </property>
  </object>
  <tx:advice id="Firstadvice">
    <tx:attributes>
      <tx:method name="*"  rollback-for="errorException" isolation="ReadCommitted" timeout="60"/>
    </tx:attributes>
  </tx:advice>
  <aop:config>
    <aop:advisor advice-ref="Firstadvice" pointcut-ref="MyOperate" />
  </aop:config>

配置事务..总是报这个错:

Error creating object with name 'Firstadvice' : Can't resolve reference to object 'transactionManager' while setting 'transactionManager'.

请问高手为什么??