[16:52:49 ERROR]: Could not pass event PlayerCommandPreprocessEvent to RisingEmpire v1.0
org.bukkit.event.EventException
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:310) ~[1.9.jar:git-Spigot-7d15d07-c194444]
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[1.9.jar:git-Spigot-7d15d07-c194444]
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:502) [1.9.jar:git-Spigot-7d15d07-c194444]
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:487) [1.9.jar:git-Spigot-7d15d07-c194444]
        at net.minecraft.server.v1_9_R1.PlayerConnection.handleCommand(PlayerConnection.java:1294) [1.9.jar:git-Spigot-7d15d07-c194444]
        at net.minecraft.server.v1_9_R1.PlayerConnection.a(PlayerConnection.java:1137) [1.9.jar:git-Spigot-7d15d07-c194444]
        at net.minecraft.server.v1_9_R1.PacketPlayInChat.a(PacketPlayInChat.java:45) [1.9.jar:git-Spigot-7d15d07-c194444]
        at net.minecraft.server.v1_9_R1.PacketPlayInChat.a(PacketPlayInChat.java:1) [1.9.jar:git-Spigot-7d15d07-c194444]
        at net.minecraft.server.v1_9_R1.PlayerConnectionUtils$1.run(SourceFile:13) [1.9.jar:git-Spigot-7d15d07-c194444]
        at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [?:1.8.0_91]
        at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_91]
        at net.minecraft.server.v1_9_R1.SystemUtils.a(SourceFile:45) [1.9.jar:git-Spigot-7d15d07-c194444]
        at net.minecraft.server.v1_9_R1.MinecraftServer.D(MinecraftServer.java:716) [1.9.jar:git-Spigot-7d15d07-c194444]
        at net.minecraft.server.v1_9_R1.DedicatedServer.D(DedicatedServer.java:400) [1.9.jar:git-Spigot-7d15d07-c194444]
        at net.minecraft.server.v1_9_R1.MinecraftServer.C(MinecraftServer.java:655) [1.9.jar:git-Spigot-7d15d07-c194444]
        at net.minecraft.server.v1_9_R1.MinecraftServer.run(MinecraftServer.java:554) [1.9.jar:git-Spigot-7d15d07-c194444]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_91]
Caused by: java.lang.ClassCastException: org.bukkit.inventory.ItemStack cannot be cast to org.bukkit.inventory.meta.BookMeta
        at plugin.zozidalom.risingempire.Events.onPelayerCommandPreocess(Events.java:309) ~[?:?]
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_91]
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_91]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_91]
        at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_91]
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:306) ~[1.9.jar:git-Spigot-7d15d07-c194444]
        ... 16 more