SERVER KICKING FRIENDS!!! *HELP*

[Purpleorangez]

Hi, I am running a Tekkit server (Hamachi) and the server seems to kick everyone shortly after joining who isn't on my LAN network. I have tried entirely disabling my firewall (my friend's too) and it still kicks people. Also if I look in the command prompt, it seems to kick just after trying to authenticate the client, but I'm not sure weather or not this changes anything as I have also tried running the server in offline mode. This only happens in Tekkit. PLEASE HELP!

[Teraku]

What message does it give when someone gets kicked? Is the connection lost, or is it a Login Error?

[Purpleorangez]

It's some random thin like java.lang.connection.reset or something like that

It's just extremely irritating and I wasn't sure what is causing it.