Alarm BroadcastReceiver doesn't work on real devices

Question

I have an alarm in my Android app that work in AVD correct. But it doesn't work in real devices. What's wrong here? And that's my BroadcastReceiver:

package com.junglesofts.maraudersmap;

import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.PowerManager;
import android.widget.Toast;

public class Alarm extends BroadcastReceiver 
{    
     @Override
     public void onReceive(Context context, Intent intent) 
     {   
         PowerManager pm = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
         PowerManager.WakeLock wl = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "");
         wl.acquire();

         // Put here YOUR code.
         Toast.makeText(context, "Alarm!!!!!!!!!!", Toast.LENGTH_LONG).show(); // For example

         wl.release();
     }

 public void SetAlarm(Context context)
 {
     AlarmManager am=(AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
     Intent i = new Intent(context, Alarm.class);
     PendingIntent pi = PendingIntent.getBroadcast(context, 0, i, 0);
     am.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(), 1000 * 10 * 1, pi); // Millisec * Second * Minute
 }

 public void CancelAlarm(Context context)
 {
     Intent intent = new Intent(context, Alarm.class);
     PendingIntent sender = PendingIntent.getBroadcast(context, 0, intent, 0);
     AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
     alarmManager.cancel(sender);
 }
}

I comment my Androidmanifest too.