Zend框架 - 致命错误：找不到接口'Zend \ Stdlib \ DispatchableInterface'

Question

我第一次使用Zend框架。我收到了这个错误：

  

致命错误：找不到接口'Zend \ Stdlib \ DispatchableInterface'   在/www/htdocs/w000000/myfolder/mysubfolder/Zend/Http/Client.php上线   27

以下代码来自需要Zend框架的Server Side Google Analytics：

       public function getHttpClient () {
        if(!$this->httpClient instanceof Zend_Http_Client) {
            include_once("Zend/Http/Client.php");
            $this->httpClient = new Zend_Http_Client();
            $this->httpClient->setConfig(array(
                'maxredirects' => 1,
                'timeout'      => 4
            ));
            $this->httpClient->setHeaders('Referer', "http://" . self::$trackingDomain . "/");
            $this->httpClient->setHeaders("User-Agent", "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.0.7) Gecko/2009021910 Firefox/3.0.7 (.NET CLR 3.5.30729)");
            $this->httpClient->setCookieJar();
        }
        return $this->httpClient;
    }

错误来自哪里？

谢谢你， 乌利