[13:38:37 WARN]: Exception in thread "Craft Scheduler Thread - 4860"
[13:38:37 WARN]: org.apache.commons.lang.UnhandledException: Plugin Anti-ForceField v1.3.5 generated an exception while executing task 895
        at org.bukkit.craftbukkit.v1_7_R3.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:56)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:745)
Caused by: java.util.ConcurrentModificationException
        at java.util.HashMap$HashIterator.nextEntry(HashMap.java:926)
        at java.util.HashMap$KeyIterator.next(HashMap.java:960)
        at com.google.common.collect.StandardTable$RowMap$EntryIterator.next(StandardTable.java:1000)
        at com.google.common.collect.StandardTable$RowMap$EntryIterator.next(StandardTable.java:992)
        at com.google.common.collect.Iterators$8.next(Iterators.java:781)
        at me.heirteir.antiff.EntityHider.removeEntity(EntityHider.java:158)
        at me.heirteir.antiff.listeners.PlayerListener$2$1.run(PlayerListener.java:152)
        at org.bukkit.craftbukkit.v1_7_R3.scheduler.CraftTask.run(CraftTask.java:58)
        at org.bukkit.craftbukkit.v1_7_R3.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:53)
        ... 3 more