Estoy tratando de hacer una página de registro de una actividad de Android conectando los datos a mi base de datos, obtengo este error "org.json.JSONException: Value

En primer lugar, ¿podría alguien aconsejarme sobre cómo depurar mi programa cuando utilizo una base de datos mysql con un script php para una aplicación de Android? Porque normalmente uso el log cat pero aquí los errores no son tan claros: S ...

Aquí está el código de actividad:

<code>public class Subscribe extends Activity {

    Button bSubscribe;
    EditText etPwdSub, etPwdConf, etLoginSub, etNameSub, etFnSub;
    String result = null;
    InputStream is = null;
    String donnees = "";

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.subscribe);

        etLoginSub = (EditText) findViewById(R.id.etLoginSub);
        etPwdSub = (EditText) findViewById(R.id.etPwdSub);
        etPwdConf = (EditText) findViewById(R.id.etPwdConf);
        etNameSub = (EditText) findViewById(R.id.etNameSub);
        etFnSub = (EditText) findViewById(R.id.etFnSub);

        bSubscribe = (Button) findViewById(R.id.bSubscribe);        
        bSubscribe.setOnClickListener(new View.OnClickListener() {

            public void onClick(View v) {

                Pattern p = Pattern.compile(".+@.+\\.[a-z]+");
                Matcher m = p.matcher(etLoginSub.getEditableText());

                if (m.matches() == false) {

                    Toast.makeText(
                            getBaseContext(),
                            "Le champs email ne correspond pas au format d'une adresse mail",
                            Toast.LENGTH_SHORT).show();
                } else {

                    // autre méthode : etPwdSub.equals("")
                    if (etPwdSub.getEditableText() != null
                            && etPwdConf.getEditableText() != null
                            && etNameSub.getEditableText() != null
                            && etFnSub.getEditableText() != null) {

                        if (etPwdSub.getEditableText().toString().equals(etPwdConf.getEditableText().toString())) {

                            ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();

                            nameValuePairs.add(new BasicNameValuePair("login", etLoginSub.getText().toString()));
                            nameValuePairs.add(new BasicNameValuePair("pwd", etPwdConf.getText().toString()));
                            nameValuePairs.add(new BasicNameValuePair("name", etNameSub.getText().toString()));
                            nameValuePairs.add(new BasicNameValuePair("firstname", etFnSub.getText().toString()));                          

                            try {
                                // commandes httpClient
                                HttpClient httpclient = new DefaultHttpClient();


                                HttpPost httppost = new HttpPost(
                                        "http://192.168.1.101/spotnshare/subscribe.php");

                                httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));

                                HttpResponse response = httpclient.execute(httppost);

                                HttpEntity entity = response.getEntity();
                                is = entity.getContent();

                            } catch (Exception e) {
                                Log.i("taghttppost", "" + e.toString());
                                Toast.makeText(getBaseContext(), e.toString(), Toast.LENGTH_LONG)
                                        .show();
                            }

                            try {
                                BufferedReader reader = new BufferedReader(new InputStreamReader(
                                        is, "UTF-8"));

                                StringBuilder sb = new StringBuilder();

                                String line = null;

                                while ((line = reader.readLine()) != null) {
                                    sb.append(line + "\n");
                                }

                                is.close();

                                result = sb.toString();
                            } catch (Exception e) {
                                Log.i("tagconvertstr", "" + e.toString());
                            }

                            try {
                                JSONObject jObj = new JSONObject(result);

                                    donnees = jObj.getString("message");

                                    Intent ourIntent = new Intent(Subscribe.this,
                                            SubscribeMess.class);

                                    // objet qui vas nous permettre de passe des variables ici la
                                    // variable passInfo
                                    Bundle objetbunble = new Bundle();          
                                    objetbunble.putString("message", donnees);
                                    ourIntent.putExtras(objetbunble);               // on passe notre objet dans l'intent

                                    // on appelle notre activité
                                    startActivity(ourIntent);                                   

                            } catch (JSONException e) {
                                Log.i("tagjsonexp", "" + e.toString());
                            } catch (ParseException e) {
                                Log.i("tagjsonpars", "" + e.toString());
                            }


                        } else {
                            Dialog d = new Dialog(Subscribe.this);
                            d.setTitle(etPwdSub.getEditableText() +" "+etPwdConf.getEditableText());
                            d.show();
                        }

                    } else {
                        Dialog d = new Dialog(Subscribe.this);
                        d.setTitle("Fill in all the fields !");
                        d.show();
                    }

                }
            }
        });

    }

    protected void onPause() {
        super.onPause();
        finish();
    }
}
</code>

y aquí está el script php:

<code><?php

if( isset($_POST['login']) && isset($_POST['pwd']) && isset($_POST['name']) && isset($_POST['firstname'])) {

    include("connexion_bdd.php");

    if(connexionBDD() == 1){

        $login = $_POST['login'];
        $pwd = $_POST['pwd'];
        $name = $_POST['name'];
        $firstname = $_POST['firstname'];

        $sql = "SELECT colUserID
                FROM userTable 
                WHERE colUserLogin = '".$login."' ";

        $req = mysql_query($sql);
        $resultat=mysql_num_rows($req); 

        if($resultat==0){
            $temps = time();
            $clef = md5($login . $temps);

            $req = mysql_query("INSERT INTO userTable(colUserLogin, colUserPwd, colUserName, colUserFirstname, colUserKey, colUserDate)
                                        VALUES( '$login', '$pwd', '$name', '$firstname', '$clef', '$temps')");

            if($req){
                    $destinataire = $login;
                    $sujet ="Welcome on SnSR";
                    $from = "From: [email protected] \r\n";
                    $from .= "Content-Type: text/html; charset=us-ascii\r\n";

                    $message = ' Clic on the link below :<br/>
                    <a href="http://localhost/spotnshare/validation_mail.php?usrk='.$clef.' ">
                        Registration confirmation.
                    </a> ';

                    ini_set('SMTP','relay.skynet.be');

                    if(mail($destinataire,$sujet,$message,$from)){
                        $msg = 'Check your mailbox to activate your account !'; 
                    }           
                    else{
                        $msg = 'Problem sending you the activation mail !'; 
                        $req = mysql_query("DELETE FROM userTable WHERE colUserLogin = '".$pseudo."' ");
                    }
            }
            else{
                $msg = 'Problem inserting you in our database !';
            }
        }else{
                $msg = 'This email has already been used !';
        }
        mysql_free_result ($req);   

    }else{
        $msg = "Connexion problem with de DB"
        print(json_encode(array("message" => $msg)));       
    }

}else{
        $msg = "Couldn't treat your datas"
}

print(json_encode(array("message" => $msg)));

?>
</code>