Help Problem With Radius

hello all and happy new year.

i have a problem with radius npc. i have make a code for use some effect etc

doorman npc hit alter of wind is only a effect but in a radius doorman can't see target

here is code

public class L2SpecialEffects implements Runnable
{
		
	private L2MonsterInstance isNpc;
	
	public L2SpecialEffects(L2MonsterInstance GetNpc)
	{
		this.isNpc = GetNpc;
	}

	
		@Override
		public void run()
		{
			if (isNpc.isDead())
				return;

			for (final L2Object o : isNpc.getKnownList().getKnownCharactersInRadius(20000))
            {
				if(o instanceof L2MonsterInstance)
				{
					L2MonsterInstance mob = (L2MonsterInstance) o;
					
					if(mob.isDead() || mob.isInCombat())
					{
						continue;
					}
					
					if(mob.getNpcId() == 300)
					{
						isNpc.broadcastPacket(new MagicSkillUser(mob, mob, 3157, 1, 800, 0));
					}
				}
            }
		}
	}

i need tell me where is the problem tnx