App crashes in Step 2 of the wizard

06-29 07:51:45.326    1822-1822/com.muzima D/SntpClient﹕ request time failed:
    android.os.NetworkOnMainThreadException
            at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1145)
            at java.net.InetAddress.lookupHostByName(InetAddress.java:385)
            at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
            at java.net.InetAddress.getByName(InetAddress.java:289)
            at com.muzima.service.SntpClient.requestTime(SntpClient.java:77)
            at com.muzima.service.SntpService.getLocalTime(SntpService.java:19)
            at com.muzima.view.cohort.CohortWizardActivity$3$1.onPostExecute(CohortWizardActivity.java:161)
            at com.muzima.view.cohort.CohortWizardActivity$3$1.onPostExecute(CohortWizardActivity.java:136)
            at android.os.AsyncTask.finish(AsyncTask.java:632)
            at android.os.AsyncTask.access$600(AsyncTask.java:177)
            at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:645)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5017)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
            at dalvik.system.NativeStart.main(Native Method)

@Override
protected void onPostExecute(int[] result) {
    dismissProgressDialog();
    if (result[0] != SUCCESS) {
        Toast.makeText(CohortWizardActivity.this, "Could not download clients", Toast.LENGTH_SHORT).show();
    }
    Log.i(TAG, "Restarting timeout timer!") ;
    ((MuzimaApplication) getApplication()).restartTimer();
    try {
        LastSyncTimeService lastSyncTimeService = ((MuzimaApplication)getApplicationContext()).getMuzimaContext().getLastSyncTimeService();
        SntpService sntpService = ((MuzimaApplication)getApplicationContext()).getSntpService();
        LastSyncTime lastSyncTime = new LastSyncTime(DOWNLOAD_COHORTS, sntpService.getLocalTime());
        lastSyncTimeService.saveLastSyncTime(lastSyncTime);
    } catch (IOException e) {
        Log.i(TAG,"Error setting cohort sync time.");
    }
    keepPhoneAwake(false) ;
    navigateToNextActivity();
}