spellbook: ArithmeticException

[Owain94]

java.lang.ArithmeticException: / by zero
    at net.runelite.client.plugins.spellbook.SpellbookPlugin.onScriptCallbackEvent(SpellbookPlugin.java:390)
    at io.reactivex.internal.observers.LambdaObserver.onNext(LambdaObserver.java:63)
    at io.reactivex.internal.operators.observable.ObservableMap$MapObserver.onNext(ObservableMap.java:62)
    at io.reactivex.internal.operators.observable.ObservableFilter$FilterObserver.onNext(ObservableFilter.java:52)
    at com.jakewharton.rxrelay2.PublishRelay$PublishDisposable.onNext(PublishRelay.java:180)
    at com.jakewharton.rxrelay2.PublishRelay.accept(PublishRelay.java:145)
    at com.jakewharton.rxrelay2.SerializedRelay.accept(SerializedRelay.java:57)
    at net.runelite.client.eventbus.EventBus.post(EventBus.java:102)
    at net.runelite.client.callback.Hooks.post(Hooks.java:161)
    at client.vmExecuteOpcode(client.java:104)
    at client.copy$runScript(client.java:154)
    at v.t(q.java:135)
    at client.runScript(client.java)
    at client.runScript(client.java:152)
    at net.runelite.client.plugins.spellbook.SpellbookPlugin.lambda$runRebuild$0(SpellbookPlugin.java:510)
    at net.runelite.client.callback.ClientThread.lambda$invoke$0(ClientThread.java:50)
    at net.runelite.client.callback.ClientThread.invoke(ClientThread.java:101)
    at net.runelite.client.callback.Hooks.clientMainLoop(Hooks.java:187)
    at client.draw(client.java:1490)
    at client.au(client.java)
    at bg.am(bg.java:381)
    at bg.run(bg.java:335)
    at java.lang.Thread.run(Thread.java:835)