Minecraft Forge 1.6.2 server won't let more than one player join?

Alright, so, I made a forge server for minecraft 1.6.2 and installed a few mods. I told my friend to install the same mods and he has, (he also has forge installed as well, the client version). I have both the client and server versions downloaded, and everytime i run the server and join it, it works fine. Everything is cool until he tries to join. As soon as he joins, I'm kicked off and the game crashes. If i close Minecraft and open it again to join, his game crashes and mine works fine.
Attached is a picture of the mods I've included. Inside the folder titled "1.6.2" is CodeChickenLib-universal-1.6.2-1.0.0.24.jar. Added (1). (ô ô) i see them