Erro

package me.devilsecktor.flexkits.Warps;

import java.util.ArrayList;

import me.devilsecktor.flexkits.Main;
import me.devilsecktor.flexkits.Kits.KitManager;

import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.Location;
import org.bukkit.Material;
import org.bukkit.Server;
import org.bukkit.World;
import org.bukkit.command.Command;
import org.bukkit.command.CommandExecutor;
import org.bukkit.command.CommandSender;
import org.bukkit.configuration.file.FileConfiguration;
import org.bukkit.enchantments.Enchantment;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.block.Action;
import org.bukkit.event.player.PlayerInteractEvent;
import org.bukkit.inventory.ItemStack;
import org.bukkit.inventory.PlayerInventory;
import org.bukkit.inventory.meta.ItemMeta;
import org.bukkit.potion.PotionEffect;
import org.bukkit.potion.PotionEffectType;
import org.bukkit.scheduler.BukkitScheduler;

public class Knock
  implements Listener, CommandExecutor
{
  public static Main plugin;

  public Knock(Main main)
  {
    plugin = main;
  }

  public boolean onCommand(CommandSender sender, Command cmd, String commandLabel, String[] args)
  {
    if (cmd.getName().equalsIgnoreCase("knock"))
    {
      final Player p = (Player)sender;

      World w = Bukkit.getServer().getWorld(plugin.getConfig().getString("knock.world"));
      double x = plugin.getConfig().getDouble("knock.x");
      double y = plugin.getConfig().getDouble("knock.y");
      double z = plugin.getConfig().getDouble("knock.z");
      final Location lobby = new Location(w, x, y, z);
      lobby.setPitch((float)plugin.getConfig().getDouble("knock.pitch"));
      lobby.setYaw((float)plugin.getConfig().getDouble("knock.yaw"));
      p.getInventory().clear();
      p.setHealthScale(1.0D);
      p.sendMessage(ChatColor.GRAY + "Teleportando em 5 segundos!");
      Bukkit.getScheduler().scheduleSyncDelayedTask(plugin, new Runnable()
      {
        public void run()
        {
          p.teleport(lobby);
          p.getInventory().clear();
          p.sendMessage("");
          p.sendMessage("");
          p.sendMessage("");
          p.sendMessage("");
          p.sendMessage("");
          p.sendMessage("");
          p.sendMessage("");
          p.sendMessage("");
          p.sendMessage("");
          p.sendMessage("");
          p.sendMessage("");
          p.sendMessage("");
          p.sendMessage("");
          p.sendMessage("");
          p.sendMessage("");
          p.sendMessage("");
          p.sendMessage("");
          p.sendMessage("");
          p.sendMessage("");
          p.sendMessage(ChatColor.GRAY + "Teleportado!");
          p.setHealthScale(20.0D);
          p.getInventory().setBoots(null);
          p.getInventory().setChestplate(null);
          p.getInventory().setLeggings(null);
          p.getInventory().setHelmet(null);
          p.setHealthScale(20.0D);
    	    ItemStack stick = new ItemStack(Material.STICK);
            stick.addEnchantment(Enchantment.KNOCKBACK, 2);
      	    p.getInventory().setItem(0, stick);
          p.setFireTicks(0);
          KitManager.darSopas(p);
          for (PotionEffect effect : p.getActivePotionEffects()) {
          }
        }
      }, 90L);

      return false;
    }
    return false;
  }
}