Typo3 Formhandler验证显示白色屏幕

我完全遵循了类型3的表单处理程序“如何设置p-a-simpleform”。标准表单有效,但当我添加验证部分时,表单帖子将显示一个白色屏幕。我用了下面的打字稿。是什么原因导致验证后来自变为白色屏幕?

plugin.Tx_Formhandler.settings {   

  validators.1.class = Validator_Default
  validators.1.disabled = 0
  validators.1.config.fieldConf {
    message.errorCheck.1 = required
    message.errorCheck.2 = minLength
    message.errorCheck.2.value = 5

    sender_name.errorCheck.1 = required

    sender_email.errorCheck.1 = required
    sender_email.errorCheck.2 = email
  }

  addErrorAnchors = 1
  singleErrorTemplate {
    totalWrap = |
    singleWrap = <span style="color: red;">|</span>
  }
  errorListTemplate {
    totalWrap = <div style="color: red;">Es sind folgende Fehler aufgetreten: <ul>|</ul></div>
    singleWrap = <li>|</li>
  }

  debug = 0    
  langFile = fileadmin/templates/sandraverdijck/lang/lang-contactform.xml
  templateFile = fileadmin/templates/sandraverdijck/html/contactform.html  
  formValuesPrefix = formhandler    
  finishers {     
    1 {       
      class = Tx_Formhandler_Finisher_Mail     
    }     
    2 {       
      class = Tx_Formhandler_Finisher_SubmittedOK       
      config.returns = 1     
    }   
  } 
}