Problem FTB Infinity 1.12.1 - No Hostile Mobs Spawing

[Tunacatsubmarine]

As mentioned, when a specific player joins, the entire server crashes. When any of the other 5 players join, no issues. Attempted to delete player data, unsuccessful, attempted to reset player data using NBTExplorer, unsuccessful. Not sure what else I can try.

FTB Infinity 1.12.1
Server Specs:
Windows 7 Pro SP1 64 Bit (Up to date)
Java Version 8 Update 51
Intel Xeon E3 1230 V2
ASRock Z77Pro4
16GB DDR3 1600
NVidia GeForce GTX 750 Ti
Samsung Evo 840

CPU and GPU Temps ~20-30 C

Attached is the crash report. If there is any info I missed that you need, just let me know.
I appreciate the assistance.

Thanks!

EDIT: Discovered that Logistics Pipes may have been causing the problem. Disabled it, and that player seems to be able to join. But beyond that I have no idea. However, now the server won't naturally spawn hostile mobs, nor will using an egg spawner or regular spawner work.

EDIT 2: Ensured that the Gameplay=0 and that mobSpawning true. Still no hostile mobs naturally nor artificially.

 

[DgtlRenegade]

Can you post your server properties. Are you getting any other errors? Is logistics pipes the only mod you have disabled? I'm assuming you mean gamemode not gameplay. Gamemode=0 has nothing to do with mob spawning. Either way, you're thinking of difficulty which CANT be 0 or mobs WONT spawn.