Android Error Parsing string to json
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Need help on android =( been stuck on this for ages! My codes are as shown.

    public class AllUsersActivity extends ListActivity {
 
    // Progress Dialog
    private ProgressDialog pDialog;
 
    // Creating JSON Parser object
    JSONParser jParser = new JSONParser();
 
    ArrayList<HashMap<String, String>> usersList;
 
    // url to get all users list
    private static String url_all_users = "http://10.0.2.2/android_connect/get_all_users.php";
 
    // JSON Node names
    private static final String TAG_SUCCESS = "success";
    private static final String TAG_USERS = "users";
    private static final String TAG_UID = "UserID";
    private static final String TAG_FIRSTNAME = "FirstName";
 
    // users JSONArray
    JSONArray users = null;
 
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.all_users);
 
        // Hashmap for ListView
        usersList = new ArrayList<HashMap<String, String>>();
 
        // Loading users in Background Thread
        new LoadAllusers().execute();
 
        // Get listview
        ListView lv = getListView();
 
        // on seleting single product
        // launching Edit Product Screen
        lv.setOnItemClickListener(new OnItemClickListener() {
 
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                // getting values from selected ListItem
                String uid = ((TextView) view.findViewById(R.id.uid)).getText()
                        .toString();
 
                // Starting new intent
                Intent in = new Intent(getApplicationContext(),
                        UserDetailsActivity.class);
                // sending uid to next activity
                in.putExtra(TAG_UID, uid);
 
                // 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 LoadAllusers extends AsyncTask<String, String, String> {
 
        /**
         * Before starting background thread Show Progress Dialog
         * */
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(AllUsersActivity.this);
            pDialog.setMessage("Loading users. Please wait...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(false);
            pDialog.show();
        }
 
        /**
         * getting All users 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_users, "GET", params);
 
            // Check your log cat for JSON reponse
            Log.d("All users: ", json.toString());
 
            try {
                // Checking for SUCCESS TAG
                int success = json.getInt(TAG_SUCCESS);
 
                if (success == 1) {
                    // users found
                    // Getting Array of users
                    users = json.getJSONArray(TAG_USERS);
 
                    // looping through All users
                    for (int i = 0; i < users.length(); i++) {
                        JSONObject c = users.getJSONObject(i);
 
                        // Storing each json item in variable
                        String id = c.getString(TAG_UID);
                        String name = c.getString(TAG_FIRSTNAME);
 
                        // creating new HashMap
                        HashMap<String, String> map = new HashMap<String, String>();
 
                        // adding each child node to HashMap key => value
                        map.put(TAG_UID, id);
                        map.put(TAG_FIRSTNAME, name);
 
                        // adding HashList to ArrayList
                        usersList.add(map);
                    }
                } 
            } catch (JSONException e) {
                e.printStackTrace();
            }
 
            return null;
        }
 
        /**
         * After completing background task Dismiss the progress dialog
         * **/
        protected void onPostExecute(String file_url) {
            // dismiss the dialog after getting all users
            pDialog.dismiss();
            // updating UI from Background Thread
            runOnUiThread(new Runnable() {
                public void run() {
                    /**
                     * Updating parsed JSON data into ListView
                     * */
                    ListAdapter adapter = new SimpleAdapter(
                            AllUsersActivity.this, usersList,
                            R.layout.list_item, new String[] { TAG_UID,
                                    TAG_FIRSTNAME},
                            new int[] { R.id.uid, R.id.name });
                    // updating listview
                    setListAdapter(adapter);
                }
            });
 
        }
 
    }
   
Can anyone please help me! The error i've been getting is ***Error Parsing Data Org.json.JSONException: Value cannot be converted to JSONObject***

Heres the JSON string

    Array{"Users":[{"UserID":"1","FirstName":"lalawee","Email":"12345","Password":null},{"UserID":"2","FirstName":"shadowblade721","Email":"12345","Password":null},{"UserID":"3","FirstName":"dingdang","Email":"12345","Password":null},{"UserID":"4","FirstName":"solidsnake0328","Email":"12345","Password":null}],"success":1}

Is the error lying in the JSON parser class?