Divining Rods Stops You From Joining Server

[Daedric101]

Title: Divining Rods Stops You From Joining Server

Version: 3.0.3/3.0.4

OS: I don't know because it was my skype friend's computer.

Java Version: I don't know because it was my skype friend's computer, but I think he has Java 7

Description of Problem:

My friend and I were playing on my tekkit server and he just made a divining rod, he pressed 'r' to sort his inventory and suddenly his game crashed and he has a white screen. He tried to log back in but the same thing happened. However, I could see him on the server for a few seconds and then he logs off. So I put lava where he logged out and told him to log back in. When he did that, he died and dropped the divining rod, later, he was able to respawn and play on my server again. So I want to know why this happens and how to prevent it from happening because I find the divining rod very buggy and unstable. It sometimes causes my minecraft to freeze for a few seconds.

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Error Log: