php怎么调用.net的webservice？100分送上

php如何调用.net的webservice？？？100分送上
php如何调用.net的webservice？请高手赐教，我写了一面一段程序，可是总是提示错误：没有创建实例对象，大家帮我看一下，哪里错了？
客户端php程序：
require('./require/nusoap/lib/nusoap.php');
$userinfo=array('username' => 'fiekscos');
$s=new soapclient('http://www.yy-sports.com/webservice/memberinfo.asmx?WSDL');
$s->soap_defencoding = 'UTF-8';
$s->decode_utf8 = false;
$result = $s->__soapCall('ValidUserLoginName',array('UserLoginName' => $userinfo));
echo $result;
?>
服务器端.net的webservice程序：
using System;
using System.Collections;
using System.Web;
using System.Web.Services;
using System.Web.Services.Protocols;

using com.Basic;

///

///MemberInfo 的摘要说明
///

[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
//若要允许使用 ASP.NET AJAX 从脚本中调用此 Web 服务，请取消对下行的注释。
// [System.Web.Script.Services.ScriptService]
public class MemberInfo : System.Web.Services.WebService
{
//

/// SOAP认证类
///

public SecurityHeader CurrentUser
{
get { return _CurrentUser; }
set { _CurrentUser = value; }
}
private SecurityHeader _CurrentUser;

public MemberInfo()
{

//如果使用设计的组件，请取消注释以下行
//InitializeComponent();
}

private bool ValidateUser(string user, string pass)
{
Boolean reVal=false;

EDbOperator oo = new EDbOperator();
try
{
String sql = "Select Count([ID]) From WebService_User Where [Name]='{0}' And Pass='{1}' And [Status] = 1";
user = Tools.FilterSQL(user.Trim());
pass = Tools.FilterSQL(pass.Trim());
sql = String.Format(sql, user, pass);
Int32 Count = Convert.ToInt32(oo.DbOperator.ExecScalar(sql));
if (Count > 0)
{
reVal = true;
}
}
finally
{
oo.Dispose();
}

return reVal;
}

///

/// 根据系列代码,返回系列名称
///

/// 系列代码
/// 系列名称
[WebMethod(Description = "输入一个新的用户登录名称,判断是否已经注册 0为未注册 非0为已注册或出错"), SoapHeader("CurrentUser")]
public Int32 ValidUserLoginName(String UserLoginName)
{
if (!ValidateUser(CurrentUser.UserName, CurrentUser.UserPass)) { throw new Exception("出错"); }

Int32 reVal = 1;

EDbOperator oo = new EDbOperator();
try
{
String sql;
sql = "Select Count([ID]) From YY_User Where [UserName] = '" + UserLoginName + "'";
reVal = Convert.ToInt32(oo.DbOperator.ExecScalar(sql));
}
finally
{
oo.Dispose();
}

return reVal;
}

}
//自定义Soap Header　Class
public class SecurityHeader : System.Web.Services.Protocols.SoapHeader
{
public String UserName;
public String UserPass;
}

------解决方案--------------------