Internal Server Error with dimensional anchors

[Hotelmariofan]

Title: Internal Server Error with dimensional anchors

Version: 3.1.2

OS: Windows 7 Home Premium 64bit

Java Version: 1.7.0_11-b21

Description of Problem:

All of the sudden now, when I put down a dimensional anchor down and then either leave the server or that area, when I come back to right click on it, I get kicked and receive this error. If I just set it down and then right click on it, then it works. Only If I leave the area and then come back does this happen. Any idea on how to fix this?

EDIT:

Now I've learned that it is only me that has this problem. All other players on my server do not. I am the admin/OP of the server as well.

EDIT:

Alright, so I've found that it only happens if I go to the nether, if I don't, i get no error. Only after I go and come back from the nether does this happen. Then to get it to stop I have to break the anchor an replace it.

Error Messages:

Disconnected by server

Internal Server Error

Error Log:

[WARNING] Failed to handle packet: java.lang.NullPointerException

java.lang.NullPointerException

 

        at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:697)

 

        at net.minecraft.server.Packet15Place.handle(SourceFile:39)

 

        at net.minecraft.server.NetworkManager.b(NetworkManager.java:234)

 

        at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:119)

 

        at net.minecraft.server.NetworkListenThread.a(NetworkListenThread.java:83)

 

        at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:579)

 

        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:467)

 

        at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)