[19:52:32 ERROR]: Could not pass event PlayerMoveEvent to ajParkour v2.0.0-prerelease7
org.bukkit.event.EventException
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:310) ~[Spigot%20%5b1.8.8%5d.jar:git-Spigot-db6de12-18fbb24]
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[Spigot%20%5b1.8.8%5d.jar:git-Spigot-db6de12-18fbb24]
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:502) [Spigot%20%5b1.8.8%5d.jar:git-Spigot-db6de12-18fbb24]
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:487) [Spigot%20%5b1.8.8%5d.jar:git-Spigot-db6de12-18fbb24]
        at net.minecraft.server.v1_8_R3.PlayerConnection.a(PlayerConnection.java:270) [Spigot%20%5b1.8.8%5d.jar:git-Spigot-db6de12-18fbb24]
        at net.minecraft.server.v1_8_R3.PacketPlayInFlying.a(SourceFile:126) [Spigot%20%5b1.8.8%5d.jar:git-Spigot-db6de12-18fbb24]
        at net.minecraft.server.v1_8_R3.PacketPlayInFlying$PacketPlayInPosition.a(SourceFile:57) [Spigot%20%5b1.8.8%5d.jar:git-Spigot-db6de12-18fbb24]
        at net.minecraft.server.v1_8_R3.PlayerConnectionUtils$1.run(SourceFile:13) [Spigot%20%5b1.8.8%5d.jar:git-Spigot-db6de12-18fbb24]
        at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [?:1.8.0_231]
        at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_231]
        at net.minecraft.server.v1_8_R3.SystemUtils.a(SourceFile:44) [Spigot%20%5b1.8.8%5d.jar:git-Spigot-db6de12-18fbb24]
        at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:715) [Spigot%20%5b1.8.8%5d.jar:git-Spigot-db6de12-18fbb24]
        at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:374) [Spigot%20%5b1.8.8%5d.jar:git-Spigot-db6de12-18fbb24]
        at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:654) [Spigot%20%5b1.8.8%5d.jar:git-Spigot-db6de12-18fbb24]
        at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:557) [Spigot%20%5b1.8.8%5d.jar:git-Spigot-db6de12-18fbb24]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_231]
Caused by: java.lang.UnsupportedOperationException
        at java.util.AbstractList.add(Unknown Source) ~[?:1.8.0_231]
        at java.util.AbstractList.add(Unknown Source) ~[?:1.8.0_231]
        at java.util.AbstractCollection.addAll(Unknown Source) ~[?:1.8.0_231]
        at us.ajg0702.parkour.game.PkPlayer.addCommands(PkPlayer.java:213) ~[?:?]
        at us.ajg0702.parkour.Rewards.executeCommands(Rewards.java:201) ~[?:?]
        at us.ajg0702.parkour.Rewards.executeCommands(Rewards.java:196) ~[?:?]
        at us.ajg0702.parkour.Rewards.checkRewards(Rewards.java:188) ~[?:?]
        at us.ajg0702.parkour.game.PkPlayer.madeIt(PkPlayer.java:174) ~[?:?]
        at us.ajg0702.parkour.game.PkPlayer.checkMadeIt(PkPlayer.java:229) ~[?:?]
        at us.ajg0702.parkour.game.Manager.onPlayerMove(Manager.java:263) ~[?:?]
        at sun.reflect.GeneratedMethodAccessor9.invoke(Unknown Source) ~[?:?]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_231]
        at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_231]
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:306) ~[Spigot%20%5b1.8.8%5d.jar:git-Spigot-db6de12-18fbb24]
        ... 15 more