未定义变量名称空间。动作

Question

尝试使用函数loadWSDL（）时出现以下错误：

ReferenceError: Error #1065: Variable namespace is not defined.
    at mx.rpc.xml::SchemaLoader/schemaImports()
    at mx.rpc.wsdl::WSDLLoader/schemaImports()
    at mx.rpc.wsdl::WSDLLoader/resultHandler()
    at flash.events::EventDispatcher/dispatchEventFunction()
    at flash.events::EventDispatcher/dispatchEvent()
    at HTTPOperation/http://www.adobe.com/2006/flex/mx/internal::dispatchRpcEvent()
    at mx.rpc::AbstractInvoker/http://www.adobe.com/2006/flex/mx/internal::resultHandler()
    at mx.rpc::Responder/result()
    at mx.rpc::AsyncRequest/acknowledge()
    at DirectHTTPMessageResponder/completeHandler()
    at flash.events::EventDispatcher/dispatchEventFunction()
    at flash.events::EventDispatcher/dispatchEvent()
    at flash.net::URLLoader/onComplete()

代码：

var url = "ServiceURL.svc?wsdl";
        webService = new WebService();
        webService.wsdl = url;
        webService.loadWSDL();
        webService.addEventListener(LoadEvent.LOAD, BuildServiceRequest);

如何解决这个问题？当使用另一个webservice时 - 一切正常，但是这个我得到了错误。