Server Crash: SEVERE Error handling login related packet

[olive24700]

Hello, I recently set up a custom modpack for my friends and I to play on a private server. I was able to get all the mods working together just fine and we all played on the server for a couple days until one of the players logged into the server and it crashed (log pasted below). This happened once to one user and twice to another. My temporary fix to the problem has been deleting their player.dat until the problem happens again. I am not sure what is going wrong. Again this only happens to a few people and only when they log in.

 

Server Log:

http://pastebin.com/WRUNxhcb

 

Crash Report:

http://pastebin.com/c51f8ywt

 

[LexManos]

 

2014-03-11 16:41:39 [sEVERE] Encountered an unexpected exception NullPointerException

java.lang.NullPointerException

        at co.uk.flansmods.common.teams.TeamsManager.tick(TeamsManager.java:136)

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