Internal Server Error With Anvils - SMP - When you delete all the letters in the renaming area of an anvil interface. CLICK FOR INFO

What I expected to happen was...:
To rename the diamond sword like in single player

What actually happened was...:
I was kicked from the server with the message, "Internal Server Error"

Steps to Reproduce:
1. Have an enchanted diamond tool,(I had a sword) and place it in the first slot of the anvil interface with nothing in the secondary slot.
2. Click the renaming section of the interface and BACKSPACE all the letters.
3. You should now have been kicked.

Extra Info:
I had an enchanted diamond sword have used with Sharpness III, Fire Aspect II, Knockback II.
I was on a BUKKIT server