Soap 致命错误：对非对象调用成员函数

我使用以下代码从WebService发送和获取商品价格：

require_once('lib/nusoap.php');

$username = 'myusername';
$password = 'mypassword';
$kol = '3000';
$weight = '200';
$state = '51';
$city = '8';
$type = '0';

$option = array('login' => $username , 'password' => $password);
$client = new SoapClient('http://www.wbservice.info/Webservice/wsdl.php',$option);
$soap = $client->getProxy(); 
$response = $soap -> GetSendPrice($kol , $weight , $state , $city , $type);
      echo $response;

但这就是我的错误：

Fatal error: Call to a member function GetSendPrice() on a non-object in /sample.php on line 20

Fatal error: Call to a member function call() on a non-object in /sample.php on line 21

我尝试以下代码：

$response = $soap ->call( 'GetSendPrice',array(30000 , 200 , 51 , 8 , 0));

返回此错误：

Fatal error: Call to a member function GetSendPrice() on a non-object in /sample.php on line 20

Fatal error: Call to a member function call() on a non-object in /sample.php on line 21

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谢谢

问题似乎出在您调用的Web服务中，而不是您用来调用它的代码中