Magento 623 error code issue

Server.php

 /**
     * Handle an xmlrpc call (actual work)
     *
     * @param Zend_XmlRpc_Request $request
     * @return Zend_XmlRpc_Response
     * @throws Zend_XmlRpcServer_Exception|Exception
     * Zend_XmlRpcServer_Exceptions are thrown for internal errors; otherwise,
     * any other exception may be thrown by the callback
     */
    protected function _handle(Zend_XmlRpc_Request $request)
    {
        $method = $request->getMethod();

        // Check for valid method
        if (!$this->_table->hasMethod($method)) {
            #require_once 'Zend/XmlRpc/Server/Exception.php';
            throw new Zend_XmlRpc_Server_Exception('Method "' . $method . '" does not exist', 620);
        }

        $info     = $this->_table->getMethod($method);
        $params   = $request->getParams();
        $argv     = $info->getInvokeArguments();
        if (0 < count($argv) and $this->sendArgumentsToAllMethods()) {
            $params = array_merge($params, $argv);
        }

        // Check calling parameters against signatures
        $matched    = false;
        $sigCalled  = $request->getTypes();

        $sigLength  = count($sigCalled);
        $paramsLen  = count($params);
        if ($sigLength < $paramsLen) {
            for ($i = $sigLength; $i < $paramsLen; ++$i) {
                $xmlRpcValue = Zend_XmlRpc_Value::getXmlRpcValue($params[$i]);
                $sigCalled[] = $xmlRpcValue->getType();
            }
        }

        $signatures = $info->getPrototypes();
        foreach ($signatures as $signature) {
            $sigParams = $signature->getParameters();
            if ($sigCalled === $sigParams) {
                $matched = true;
                break;
            }
        }
        if (!$matched) {
            #require_once 'Zend/XmlRpc/Server/Exception.php';
            throw new Zend_XmlRpc_Server_Exception('Calling parameters do not match signature', 623);
        }

        $return        = $this->_dispatch($info, $params);
        $responseClass = $this->getResponseClass();
        return new $responseClass($return);
    }