微信公众平台scancode_waitmsg如何读取到ScanResult？

SAE上部署的部分代码如下，不知为何扫描二维码或条形码后什么消息都收不到，而且提示”该公众号提供的服务出现故障，清稍后再试“。整个PHP程序语法没有错误。
case "CLICK":
$contentStr = $this->receiveClick($object); //点击事件
break;
case "scancode_waitmsg":
$contentStr = "扫码结果：".$object->ScanCodeInfo->ScanResult;
$resultStr = $this->transmitText($object, $contentStr);
break;

                              //回复文本消息
private function transmitText($object, $content)
{
    $textTpl = "<xml>
    <ToUserName><![CDATA[%s]]></ToUserName>
    <FromUserName><![CDATA[%s]]></FromUserName>
    <CreateTime>%s</CreateTime>
    <MsgType><![CDATA[text]]></MsgType>
    <Content><![CDATA[%s]]></Content>
    </xml>";
    $resultStr = sprintf($textTpl, $object->FromUserName, $object->ToUserName, time(), $content);
    return $resultStr;
}

+111111111111111111111111111111111

private function transmitText($object, $content)
{
$textTpl = "
<![CDATA[%s]]>
<![CDATA[%s]]>
%s
<![CDATA[text]]>
<![CDATA[%s]]>
";
$resultStr = sprintf($textTpl, $object->FromUserName, $object->ToUserName, time(), $content);
return $resultStr;
}