สอบถาม error ของ android กับ c#.net พอดีกำลังศึกษาครับ:-)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Services;

namespace WebService2
{
    /// <summary>//bd
    /// Summary description for Service1
    /// </summary>bd
    [WebService(Namespace = "http://192.168.0.213/WebService/")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [System.ComponentModel.ToolboxItem(false)]
    // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. 
    // [System.Web.Script.Services.ScriptService]
    public class Service1 : System.Web.Services.WebService
    {

        [WebMethod]
        public string add(int param1, int param2)
        {
            try
            {
                int sum = param1 + param2;
                return sum.ToString();
            }
            catch { return "Value is wrong"; }
        }
    }
}

package com.example.add;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
 
 
import android.widget.Button;
import android.widget.EditText;
 
import org.ksoap2.SoapEnvelope;
import org.ksoap2.serialization.SoapObject;
 
import org.ksoap2.serialization.SoapSerializationEnvelope;
import org.ksoap2.transport.HttpTransportSE;
//BD
 
public class FeedDataWebService2s extends Activity implements OnClickListener {
 
    private static String SOAP_ACTION = "http://192.168.0.213/WebService/add";
    private static String NAMESPACE = "http://192.168.0.213/WebService/";
    private static String METHOD_NAME = "add";
    private static String URL = "http://192.168.0.213/WebService/service.asmx?WSDL";
 
    Button btnAns;
    EditText edt_Param1,edt_Param2,edt_Ans;
 
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activitymain);
 
        btnAns = (Button)findViewById(R.id.btn_Ans);
        edt_Param1 = (EditText)findViewById(R.id.edit_Param1);
        edt_Param2 = (EditText)findViewById(R.id.edit_Param2);
        edt_Ans = (EditText)findViewById(R.id.edit_Ans);
        btnAns.setOnClickListener(this); // Link Event Button
 
    }
 
    public void onClick(View arg0) {
        //Initialize soap request + add parameters
        SoapObject request = new SoapObject(NAMESPACE, METHOD_NAME);
        String param1 = edt_Param1.getText().toString();
        String param2 = edt_Param2.getText().toString();
    //
        //Use this to add parameters
        request.addProperty("param1",Integer.valueOf(param1));
        request.addProperty("param2",Integer.valueOf(param2));
 
        //Declare the version of the SOAP request
        SoapSerializationEnvelope envelope =
              new SoapSerializationEnvelope(SoapEnvelope.VER11);
        envelope.dotNet = true;
        envelope.setOutputSoapObject(request);
        HttpTransportSE androidHttpTransport = new HttpTransportSE(URL);
        try {
            //this is the actual part that will call the webservice
            androidHttpTransport.call(SOAP_ACTION , envelope);
 
        } catch (Exception e) {
            e.printStackTrace();
        }
 
        SoapObject result = (SoapObject)envelope.bodyIn;
        if(result != null){
            edt_Ans.setText(result.getProperty(0).toString());
        }
    }
}