[URGENT] Error: Is it up to date/Plugin already initialized

Error - http://pastebin.com/ESqg5nBm

Code:

package com.Chat;
 
import org.bukkit.ChatColor;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.player.AsyncPlayerChatEvent;
import org.bukkit.plugin.PluginManager;
import org.bukkit.plugin.java.JavaPlugin;
 
public class Main extends JavaPlugin implements Listener {
 
public void onEnable(){
PluginManager pm = getServer().getPluginManager();
pm.registerEvents(new Main(), this);   
}
 
@EventHandler
public void onChat(AsyncPlayerChatEvent event){
Player player = event.getPlayer();
 
if(player.hasPermission("chatformat.default")){
event.setFormat(ChatColor.GRAY + "%s" + ChatColor.DARK_GRAY + " >> " + ChatColor.GRAY + "%s");
 
            }
        }
 
}