Odd Error on my CraftBukkit Server

Okay, so, recently, we were getting some minor lag, but all of a sudden, the server got very laggy and crashed.

When we logged back on a random chunk had appeared out of nowhere and we can't destroy a single block of it. It looks like a replica of another chunk, but when we get near it, the lag starts up again.

I am using the latest CraftBukkit and use Minecraft 1.8.1. I also use pail with it, but that all came with CraftBukkit.

We are really confused, so if someone could help us, we would REALLY appreciate it. Thanks!

EDIT: Another thing is that Pail stops working, so I have to stop the server ingame or by closing the black command box. Also, there is almost NO lag when you are away from this mysterious chunk.

EDIT TWO: Even now, I am logged on, but my black command box is going wild with [Severe] Errors such as ThreadServerApplication and WorldServer and stuff like that, but it all says before it: at net.minecraft.server

PLEASE HELP!!!

 

You might have a corrupted chunk, run your world through chunkster or MCEdit. If that fails restore worlds with backups.
Always keep backups and backup before you do this.

 

Okay, I'll try that. Thanks!

I am sorry, I am very confused with Chunkster, and MCEdit isn't working. I am not sure if I had any backups of the server before now. So... Do you know how to use Chunkster?

EDIT: Wait, I did it... But the thing opened, found a directory, and then closed... Does this mean it might be fixed?

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

I've never used it, but I can find you a tutorial for it.

Edit: http://youtu.be/l39UMtbuK2I

 

Thanks, but still, nothing is working... Maybe I should just fence off that area in my server so that the lag doesn't start?


EDIT: OH! NEVERMIND! I deleted the chunk using MCEdit, and when I got close to the chunk, it just reloaded, uncorrupted. Thank you saul!