android - Google Maps gets crash between two activity

I am using google Maps in my application. There is a
button on page on clicking first time the google Maps is loaded properly but again going
to that page and clicking that button crashes my
app.

This is my
code:

public class GoogleMaps
            extends Activity {

 MapFragment googleMapFragment =
            null;
 private static GoogleMap googleMap = null;
 private String
            provider;
 MarkerOptions marker;

 double latitude,
            longitude;
 private LocationManager locationManager;
 ParseGeoPoint
            myLatLng[];
 int count_place, i = 0;


            @Override
 protected void onCreate(Bundle savedInstanceState) {
 //
            TODO Auto-generated method stub

            super.onCreate(savedInstanceState);

            setContentView(R.layout.googlemap_view);

 try {

            initilizeMap();
 initParse();
 } catch (Exception e) {
 //
            TODO: handle exception
 Toast.makeText(getApplicationContext(),
            e.toString(),
 Toast.LENGTH_SHORT).show();
 }

            }


 private void initParse() {
 // TODO
            Auto-generated method stub
 Parse.initialize(this, "key","key");

            ParseObject plcobj = new ParseObject("Details");
 getLatLong();

            ParseGeoPoint myGeoPiont = new ParseGeoPoint(latitude, longitude);

            ParseGeoPoint userLocation = (ParseGeoPoint) plcobj.get("location");
 final
            ParseQuery query = ParseQuery.getQuery("Details");

            query.whereNear("location", myGeoPiont);

            query.setLimit(10);

 query.whereWithinKilometers("location",
            myGeoPiont, 10);
 query.findInBackground(new FindCallback()
            {

 @Override
 public void done(List objects,
            ParseException e) {
 // TODO Auto-generated method stub


            if (e == null) {
 Iterator Itr = objects.iterator();
 while
            (Itr.hasNext()) {

 ParseObject plcObjNext = (ParseObject)
            Itr.next();
 myLatLng[i] = plcObjNext.getParseGeoPoint("location");

            i++; // Line 76

 }
 }
 }

            });
 }


 private void initilizeMap()
            {
 if (googleMap == null) {
 googleMapFragment = ((MapFragment)
            getFragmentManager()
 .findFragmentById(R.id.map));
 googleMap =
            googleMapFragment.getMap();

            googleMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);

 if (googleMap ==
            null) {
 Toast.makeText(getApplicationContext(),
 "Sorry! unable to
            create maps", Toast.LENGTH_SHORT)

 .show();
 }

            googleMap.setMyLocationEnabled(true);
 Log.e("Maps",
            "------EOC-------");
 // Get the location manager


            }
 }

 public void getLatLong() {


            GPSTracker gps = new GPSTracker(GoogleMaps.this);
 if (gps.canGetLocation())
            {
 longitude = gps.getLongitude();
 latitude =
            gps.getLatitude();
 Toast.makeText(getApplicationContext(), longitude + " " +
            latitude,
 Toast.LENGTH_SHORT).show();
 } // return boolean
            true/false
 else {
 gps.showSettingsAlert();

            }


            }
}

This is my log:

10-18 13:37:24.219
            E/AndroidRuntime(21624): FATAL EXCEPTION: main
10-18 13:37:24.219
            E/AndroidRuntime(21624): java.lang.NullPointerException
10-18 13:37:24.219
            E/AndroidRuntime(21624): at
            com.example.restaurantfinder.GoogleMaps$1.done(GoogleMaps.java:76)

10-18
            13:37:24.219 E/AndroidRuntime(21624): at
            com.parse.FindCallback.internalDone(FindCallback.java:45)
10-18 13:37:24.219
            E/AndroidRuntime(21624): at
            com.parse.FindCallback.internalDone(FindCallback.java:1)
10-18 13:37:24.219
            E/AndroidRuntime(21624): at com.parse.Parse$6$1.run(Parse.java:888)
10-18
            13:37:24.219 E/AndroidRuntime(21624): at
            android.os.Handler.handleCallback(Handler.java:605)
10-18 13:37:24.219
            E/AndroidRuntime(21624): at
            android.os.Handler.dispatchMessage(Handler.java:92)
10-18 13:37:24.219
            E/AndroidRuntime(21624): at android.os.Looper.loop(Looper.java:137)
10-18
            13:37:24.219 E/AndroidRuntime(21624): at
            android.app.ActivityThread.main(ActivityThread.java:4517)
10-18 13:37:24.219
            E/AndroidRuntime(21624): at java.lang.reflect.Method.invokeNative(Native
            Method)
10-18 13:37:24.219 E/AndroidRuntime(21624): at
            java.lang.reflect.Method.invoke(Method.java:511)
10-18 13:37:24.219
            E/AndroidRuntime(21624): at
            com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:993)

10-18
            13:37:24.219 E/AndroidRuntime(21624): at
            com.android.internal.os.ZygoteInit.main(ZygoteInit.java:760)
10-18
            13:37:24.219 E/AndroidRuntime(21624): at dalvik.system.NativeStart.main(Native
            Method)