Problem FTB Ultimate crashing

[PhanaticD]

Hi I keep getting this crash on my server, what can I do to fix it? If you need the entire stack trace please just ask

"Server thread" RUNNABLE
        at bq.b(NBTTagCompound.java:415)
        at bq.b(NBTTagCompound.java:415)
        at ur.l(ItemStack.java:383)
        at codechicken.xycraftcopy.core.inventory.InventorySensor.reset(InventorySensor.java:105)
        at soaryn.xycraft.machines.block.TileFabricator.g(TileFabricator.java:301)
        at yc.h(World.java:2607)
        at in.h(WorldServer.java:701)
        at net.minecraft.server.MinecraftServer.r(MinecraftServer.java:845)
        at ho.r(DedicatedServer.java:309)
        at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:746)
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:633)
        at fy.run(ThreadMinecraftServer.java:16)