Error converting String to JSONObject

I'm trying to develop an android application that consumes a Web-Service but whenever I try to run a query in the database it returns me this error:

  

Error parsing data org.json.JSONException: Value

In my LogCat:

02-22 15:37:32.250: I/Choreographer(1446): Skipped 232 frames!  The application may be doing too much work on its main thread.
02-22 15:37:36.712: I/Choreographer(1446): Skipped 46 frames!  The application may be doing too much work on its main thread.
02-22 15:37:37.959: I/Choreographer(1446): Skipped 112 frames!  The application may be doing too much work on its main thread.
02-22 15:37:38.611: E/JSON Parser(1446): Error parsing data org.json.JSONException: Value <br of type java.lang.String cannot be converted to JSONObject
02-22 15:37:38.612: D/All Products:(1446): {}
02-22 15:37:38.612: W/System.err(1446): org.json.JSONException: No value for success
02-22 15:37:38.613: W/System.err(1446):     at org.json.JSONObject.get(JSONObject.java:389)
02-22 15:37:38.613: W/System.err(1446):     at org.json.JSONObject.getInt(JSONObject.java:478)
02-22 15:37:38.614: W/System.err(1446):     at br.com.products.AllProductsActivity$LoadAllProducts.doInBackground(AllProductsActivity.java:134)
02-22 15:37:38.614: W/System.err(1446):     at br.com.products.AllProductsActivity$LoadAllProducts.doInBackground(AllProductsActivity.java:1)
02-22 15:37:38.684: W/System.err(1446):     at android.os.AsyncTask$2.call(AsyncTask.java:288)
02-22 15:37:38.685: W/System.err(1446):     at java.util.concurrent.FutureTask.run(FutureTask.java:237)
02-22 15:37:38.693: W/System.err(1446):     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
02-22 15:37:38.693: W/System.err(1446):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
02-22 15:37:38.693: W/System.err(1446):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
02-22 15:37:38.694: W/System.err(1446):     at java.lang.Thread.run(Thread.java:818)
02-22 15:37:39.680: I/Choreographer(1446): Skipped 184 frames!  The application may be doing too much work on its main thread.
02-22 15:37:41.397: I/Choreographer(1446): Skipped 184 frames!  The application may be doing too much work on its main thread.

It says that the error is in theInBackground method of line 134, and what it has in it is:

int success = json.getInt(TAG_SUCCESS);

My Class that granted this query:

AllProductsActivity.java

package br.com.products;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import org.apache.http.NameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.ListActivity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;

public class AllProductsActivity extends ListActivity {

    // Progress Dialog
    private ProgressDialog pDialog;

    // Creating JSON Parser object
    JSONParser jParser = new JSONParser();

    ArrayList<HashMap<String, String>> productsList;

    // url to get all products list
    private static String url_all_products = "http://XXX.XXX.X.X/android_connect/get_all_products.php";

    // JSON Node names
    private static final String TAG_SUCCESS = "success";
    private static final String TAG_PRODUCTS = "products";
    private static final String TAG_PID = "pid";
    private static final String TAG_NAME = "name";

    // products JSONArray
    JSONArray products = new JSONArray();

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_all_products);

        // Hashmap for ListView
        productsList = new ArrayList<HashMap<String, String>>();

        // Loading products in Background Thread
        new LoadAllProducts().execute();

        // Get listview
        ListView lv = getListView();

        // on seleting single product
        // launching Edit Product Screen
        lv.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                // getting values from selected ListItem
                String pid = ((TextView) view.findViewById(R.id.pid)).getText()
                        .toString();

                // Starting new intent
                Intent in = new Intent(getApplicationContext(),
                        EditProductActivity.class);
                // sending pid to next activity
                in.putExtra(TAG_PID, pid);

                // starting new activity and expecting some response back
                startActivityForResult(in, 100);
            }
        });

    }

    // Response from Edit Product Activity
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        // if result code 100
        if (resultCode == 100) {
            // if result code 100 is received
            // means user edited/deleted product
            // reload this screen again
            Intent intent = getIntent();
            finish();
            startActivity(intent);
        }

    }

    /**
     * Background Async Task to Load all product by making HTTP Request
     * */
    class LoadAllProducts extends AsyncTask<String, String, String> {

        /**
         * Before starting background thread Show Progress Dialog
         * */
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(AllProductsActivity.this);
            pDialog.setMessage("Loading products. Please wait...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(false);
            pDialog.show();
        }

        /**
         * getting All products from url
         * */
        protected String doInBackground(String... args) {
            // Building Parameters
            List<NameValuePair> params = new ArrayList<NameValuePair>();
            // getting JSON string from URL
            JSONObject json = jParser.makeHttpRequest(url_all_products, "GET", params);

            // Check your log cat for JSON reponse
            Log.d("All Products: ", json.toString());

            try {
                // Checking for SUCCESS TAG
                int success = json.getInt(TAG_SUCCESS);

                if (success == 1) {
                    // products found
                    // Getting Array of Products
                    products = json.getJSONArray(TAG_PRODUCTS);

                    // looping through All Products
                    for (int i = 0; i < products.length(); i++) {
                        JSONObject c = products.getJSONObject(i);

                        // Storing each json item in variable
                        String id = c.getString(TAG_PID);
                        String name = c.getString(TAG_NAME);

                        // creating new HashMap
                        HashMap<String, String> map = new HashMap<String, String>();

                        // adding each child node to HashMap key => value
                        map.put(TAG_PID, id);
                        map.put(TAG_NAME, name);

                        // adding HashList to ArrayList
                        productsList.add(map);
                    }
                } else {
                    // no products found
                    // Launch Add New product Activity
                    Intent i = new Intent(getApplicationContext(),
                            NewProductActivity.class);
                    // Closing all previous activities
                    i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                    startActivity(i);
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }

            return "";
        }

        /**
         * After completing background task Dismiss the progress dialog
         * **/
        protected void onPostExecute(String file_url) {
            // dismiss the dialog after getting all products
            pDialog.dismiss();
            // updating UI from Background Thread
            runOnUiThread(new Runnable() {
                public void run() {
                    /**
                     * Updating parsed JSON data into ListView
                     * */
                    ListAdapter adapter = new SimpleAdapter(
                            AllProductsActivity.this, productsList,
                            R.layout.list_item, new String[] { TAG_PID,
                                    TAG_NAME},
                            new int[] { R.id.pid, R.id.name });
                    // updating listview
                    setListAdapter(adapter);
                }
            });

        }

    }
}

I have tried and I do not think the error is coming from my php script, so much that the error points at the time of the conversion, could anyone help me?