Program: 34115
Project: 34115
Buggy source:
@Override public void onEnable(){
  plugin=this;
  saveDefaultConfig();
  saveDefaultChallengeConfig();
  saveDefaultLocale();
  if (!VaultHelper.setupEconomy()) {
    getLogger().severe("String_Node_Str");
    getServer().getPluginManager().disablePlugin(this);
    return;
  }
  if (!VaultHelper.setupPermissions()) {
    getLogger().severe("String_Node_Str");
    getServer().getPluginManager().disablePlugin(this);
    return;
  }
  loadPluginConfig();
  playersFolder=new File(getDataFolder() + File.separator + "String_Node_Str");
  if (!playersFolder.exists()) {
    playersFolder.mkdir();
  }
  getCommand("String_Node_Str").setExecutor(new IslandCmd(this));
  getCommand("String_Node_Str").setExecutor(getChallenges());
  getCommand("String_Node_Str").setExecutor(new AdminCmd(this));
  loadWarpList();
  loadMessages();
  registerEvents();
  try {
    final Metrics metrics=new Metrics(this);
    metrics.start();
  }
 catch (  final IOException localIOException) {
  }
  getServer().getScheduler().runTask(this,new Runnable(){
    @Override public void run(){
      getIslandWorld();
      getServer().getPluginManager().registerEvents(new ControlPanel(plugin),plugin);
      if (getServer().getPluginManager().isPluginEnabled("String_Node_Str")) {
        getLogger().info("String_Node_Str");
        try {
          getServer().dispatchCommand(getServer().getConsoleSender(),"String_Node_Str" + Settings.worldName + "String_Node_Str");
          getServer().dispatchCommand(getServer().getConsoleSender(),"String_Node_Str" + Settings.worldName);
        }
 catch (        Exception e) {
          getLogger().info("String_Node_Str");
          e.printStackTrace();
          getServer().getPluginManager().disablePlugin(plugin);
        }
      }
      if (getServer().getWorld(Settings.worldName).getGenerator() == null) {
        getLogger().severe("String_Node_Str");
        getLogger().severe("String_Node_Str");
        getLogger().severe("String_Node_Str");
        getLogger().severe("String_Node_Str");
        getLogger().severe("String_Node_Str");
        getLogger().severe("String_Node_Str");
        getServer().getPluginManager().disablePlugin(plugin);
      }
    }
  }
);
  if (Settings.mobAcidDamage > 0D) {
    getServer().getScheduler().scheduleSyncRepeatingTask(this,new Runnable(){
      @Override public void run(){
        List<Entity> entList=acidWorld.getEntities();
        for (        Entity current : entList) {
          if (current instanceof Monster) {
            if ((current.getLocation().getBlock().getType() == Material.WATER) || (current.getLocation().getBlock().getType() == Material.STATIONARY_WATER)) {
              ((Monster)current).damage(Settings.mobAcidDamage);
            }
          }
        }
      }
    }
,0L,20L);
  }
}

Fixed version (ground truth):
@Override public void onEnable(){
  plugin=this;
  saveDefaultConfig();
  saveDefaultChallengeConfig();
  saveDefaultLocale();
  if (!VaultHelper.setupEconomy()) {
    getLogger().severe("String_Node_Str");
    getServer().getPluginManager().disablePlugin(this);
    return;
  }
  if (!VaultHelper.setupPermissions()) {
    getLogger().severe("String_Node_Str");
    getServer().getPluginManager().disablePlugin(this);
    return;
  }
  loadPluginConfig();
  playersFolder=new File(getDataFolder() + File.separator + "String_Node_Str");
  if (!playersFolder.exists()) {
    playersFolder.mkdir();
  }
  getCommand("String_Node_Str").setExecutor(new IslandCmd(this));
  getCommand("String_Node_Str").setExecutor(getChallenges());
  getCommand("String_Node_Str").setExecutor(new AdminCmd(this));
  loadMessages();
  registerEvents();
  try {
    final Metrics metrics=new Metrics(this);
    metrics.start();
  }
 catch (  final IOException localIOException) {
  }
  getServer().getScheduler().runTask(this,new Runnable(){
    @Override public void run(){
      getIslandWorld();
      loadWarpList();
      getServer().getPluginManager().registerEvents(new ControlPanel(plugin),plugin);
      if (getServer().getPluginManager().isPluginEnabled("String_Node_Str")) {
        getLogger().info("String_Node_Str");
        try {
          getServer().dispatchCommand(getServer().getConsoleSender(),"String_Node_Str" + Settings.worldName + "String_Node_Str");
          getServer().dispatchCommand(getServer().getConsoleSender(),"String_Node_Str" + Settings.worldName);
        }
 catch (        Exception e) {
          getLogger().info("String_Node_Str");
          e.printStackTrace();
          getServer().getPluginManager().disablePlugin(plugin);
        }
      }
      if (getServer().getWorld(Settings.worldName).getGenerator() == null) {
        getLogger().severe("String_Node_Str");
        getLogger().severe("String_Node_Str");
        getLogger().severe("String_Node_Str");
        getLogger().severe("String_Node_Str");
        getLogger().severe("String_Node_Str");
        getLogger().severe("String_Node_Str");
        getServer().getPluginManager().disablePlugin(plugin);
      }
    }
  }
);
  if (Settings.mobAcidDamage > 0D) {
    getServer().getScheduler().scheduleSyncRepeatingTask(this,new Runnable(){
      @Override public void run(){
        List<Entity> entList=acidWorld.getEntities();
        for (        Entity current : entList) {
          if (current instanceof Monster) {
            if ((current.getLocation().getBlock().getType() == Material.WATER) || (current.getLocation().getBlock().getType() == Material.STATIONARY_WATER)) {
              ((Monster)current).damage(Settings.mobAcidDamage);
            }
          }
        }
      }
    }
,0L,20L);
  }
}