I get this bug over and over and... whenever creatures die

[tojammot]

Description: [describe what you were doing when the crash occurred]

NullPointerException | Open

Code: Select all

Forge Version:    1.3.16-r21506
Operating System: Windows 7 6.1 amd64
Java Version:     1.7.0_13 Oracle Corporation

java.lang.NullPointerException
   at java.util.TreeMap.getEntry(Unknown Source)
   at java.util.TreeMap.containsKey(Unknown Source)
   at java.util.TreeMap$KeySet.contains(Unknown Source)
   at forge.Card.hasProperty(Card.java:6026)
   at forge.Card.isValid(Card.java:5162)
   at forge.GameEntity.isValid(GameEntity.java:295)
   at forge.card.trigger.TriggerChangesZone.performTest(TriggerChangesZone.java:78)
   at forge.card.trigger.TriggerHandler.runSingleTrigger(TriggerHandler.java:328)
   at forge.card.trigger.TriggerHandler.runWaitingTrigger(TriggerHandler.java:252)
   at forge.card.trigger.TriggerHandler.runWaitingTriggers(TriggerHandler.java:193)
   at forge.game.GameAction.checkStateEffects(GameAction.java:1059)
   at forge.game.phase.PhaseHandler.handleBeginPhase(PhaseHandler.java:351)
   at forge.gui.InputProxy$1.run(InputProxy.java:69)
   at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
   at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
   at java.lang.Thread.run(Unknown Source)


[tojammot]

Also, it has been working fine but changed to this (making the game unplayable) and i don't know how to fix it.