SOLVEDWhen a second player joins my server the other one disconnects. "fatal error"

[VenomFrog]

Hello, ive been making a modpack and modding a server lately, all is going well until i tested it with 2 computers in my own home. Started up a server, logged into a second acct, downloaded the pack and tried joining the other player and as soon as the other player (Miner_Rondor) joins, The main character (VenomFrig) disconnects with "Fatal Error: This Connection is terminated"

I dont know whats going on. Its not a Cauldron1307 problem because when i remove all the mods from the server and restart it, both can join and play. Not too sure what is going on.

Here is a link to the latest server log
https://www.dropbox.com/home/Minecraft?preview=fml-server-latest.txt

Here is one of the clients latest log

https://www.dropbox.com/home/Minecraft?preview=fml-client-3.txt

Hopefully someone can help me find out whats wrong :/ Each person can join the server just fine on their own, play around and after a few hours of testing on each no errors or crashes. UNLESS someone else joins them. Not too sure why, there isnt a crash report either, i just simply get disconnected.

Client and server are using Forge 1.7.10 1307

Server is using Cauldron1307 with Craftbukkit1307, Thank you for the help!

 

I THINK that it may be a mod issue, and i pray that Snow can help :/ He seems the most knowledgeable here! But i dont know. I'm so lost at the moment.

PSA: ThaumicHorizons 1.1 will NOT LET a second player join. Removed ThaumicHorizons 1.1 and players could join!