Membuat Login Register

Saya ingin bertanya membuat login menggunakan http, ketika di running terdapat banyak error salah satunya seperti ini

 AndroidRuntime(1664): 	at com.example.login_http.MainActivity.readWebpage(MainActivity.java:141)

ini coding phpnya

koneksi.php

<?php

include"koneksi.php";

    $id_pln   = $_GET['id_pln'];        //get nilai user from client
	$password = md5($_GET['passnya']);    //get nilai pass from client
	$sret = '';

//	$query = mysql_query("SELECT * FROM tbluser where username ='".$user."' and password='".$password."'" );
    $query = mysql_query("SELECT * FROM t_daftar where id_pln ='$id_pln' and passnya='$password'" );
	if($query){

	$sret = 'Login Success';
	}else{

	$sret = 'Login Fail, User dan Password Salah';
	}
	echo $sret;

?>

ini code untuk android nya

 package com.example.login_http;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;

import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends Activity {

	private EditText txt_id;
	private EditText txtPassword;
	private EditText txtStatus;
	private Button btnLogin,btnregister;
	private String surl = "http://192.168.0.99/PowerMonitor/latihan_login.php";
	/**
	 * Method yang dipanggil pada saat aplikaasi dijalankan
	 * */
	@Override
	public void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);

		txt_id     = (EditText) findViewById(R.id.txt_id);
		txtPassword = (EditText) findViewById(R.id.txtPassword2);
		txtStatus   = (EditText) findViewById(R.id.txtStatus);
		btnLogin    = (Button) findViewById(R.id.btnLogin);
		btnregister = (Button)findViewById(R.id.btnDaftar);

		/**
		 *  Method untuk memanggil form Registrasi
		 */

        btnregister.setOnClickListener(new View.OnClickListener()
        {
			@Override
			public void onClick(View view) {
				Intent i = new Intent(getApplicationContext(), Register.class);
				startActivity(i);

			}
		});
    // Close Registrasi.java

		//daftarkan even onClick pada btnLogin
		 btnLogin.setOnClickListener(new Button.OnClickListener(){
	     public void onClick(View v){
	         	readWebpage(v);
	            }
	        });
       	}

	/**
	 * Method untuk Mengirimkan data keserver
	 *
	 */
	public String getRequest(String Url){
       String sret;
        HttpClient client = new DefaultHttpClient();
        HttpGet request = new HttpGet(Url);
        try{
            HttpResponse response = client.execute(request);
            sret= request(response);
        }catch(Exception ex){
           sret= "Failed Connect to server!";
        }
        return sret;

    }
	/**
	 * Method untuk Menerima data dari server
	 * @param response
	 * @return
	 */
	public static String request(HttpResponse response){
        String result = "";
        try{
            InputStream in = response.getEntity().getContent();
            BufferedReader reader = new BufferedReader(new InputStreamReader(in));
            StringBuilder str = new StringBuilder();
            String line = null;
            while((line = reader.readLine()) != null){
                str.append(line + "\n");
            }
            in.close();
            result = str.toString();
        }catch(Exception ex){
            result = "Error";
        }
        return result;
    }

	/**
	 * Class CallWebPageTask untuk implementasi class AscyncTask
	 */
	private class CallWebPageTask extends AsyncTask<String, Void, String> {

		private ProgressDialog dialog;
		protected Context applicationContext;

		@Override
		protected void onPreExecute() {
			this.dialog = ProgressDialog.show(applicationContext, "Login Process", "Please Wait...", true);
		}

	    @Override
	    protected String doInBackground(String... urls) {
	      String response = "";
	      response = getRequest(urls[0]);
	      return response;
	    }

	    @Override
	    protected void onPostExecute(String result) {
	    	this.dialog.cancel();
	    	txtStatus.setText(result);
	    }
	  }





	  public void readWebpage(View view) {
	    CallWebPageTask task = new CallWebPageTask();
	    task.applicationContext = MainActivity.this;
	    String url =surl+"?id_pln="+txt_id.getText().toString()+"&passnya="+txtPassword.getText().toString();
	    task.execute(new String[] { url });

	  }

}

mohon masukanya ,terima kasih