Cant spawn random crates

[12:32:53] [Server thread/INFO]: Bob1nz issued server command: /crate spawn
[12:32:53] [Server thread/ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'crate' in plugin MysteryCrates v1.9.8.9.3
	at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[spigot-1.8.jar:git-Spigot-330d66b-fe41b01]
	at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:141) ~[spigot-1.8.jar:git-Spigot-330d66b-fe41b01]
	at org.bukkit.craftbukkit.v1_8_R1.CraftServer.dispatchCommand(CraftServer.java:642) ~[spigot-1.8.jar:git-Spigot-330d66b-fe41b01]
	at net.minecraft.server.v1_8_R1.PlayerConnection.handleCommand(PlayerConnection.java:1115) [spigot-1.8.jar:git-Spigot-330d66b-fe41b01]
	at net.minecraft.server.v1_8_R1.PlayerConnection.a(PlayerConnection.java:950) [spigot-1.8.jar:git-Spigot-330d66b-fe41b01]
	at net.minecraft.server.v1_8_R1.PacketPlayInChat.a(PacketPlayInChat.java:26) [spigot-1.8.jar:git-Spigot-330d66b-fe41b01]
	at net.minecraft.server.v1_8_R1.PacketPlayInChat.a(PacketPlayInChat.java:53) [spigot-1.8.jar:git-Spigot-330d66b-fe41b01]
	at net.minecraft.server.v1_8_R1.PacketHandleTask.run(SourceFile:13) [spigot-1.8.jar:git-Spigot-330d66b-fe41b01]
	at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [?:1.8.0_25]
	at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_25]
	at net.minecraft.server.v1_8_R1.MinecraftServer.z(MinecraftServer.java:683) [spigot-1.8.jar:git-Spigot-330d66b-fe41b01]
	at net.minecraft.server.v1_8_R1.DedicatedServer.z(DedicatedServer.java:316) [spigot-1.8.jar:git-Spigot-330d66b-fe41b01]
	at net.minecraft.server.v1_8_R1.MinecraftServer.y(MinecraftServer.java:623) [spigot-1.8.jar:git-Spigot-330d66b-fe41b01]
	at net.minecraft.server.v1_8_R1.MinecraftServer.run(MinecraftServer.java:526) [spigot-1.8.jar:git-Spigot-330d66b-fe41b01]
	at java.lang.Thread.run(Unknown Source) [?:1.8.0_25]
Caused by: java.lang.IncompatibleClassChangeError: Found interface com.sk89q.worldguard.protection.ApplicableRegionSet, but class was expected
	at me.picknchew.mysterycrates.MysteryCrates.spawnFalling(MysteryCrates.java:1964) ~[?:?]
	at me.picknchew.mysterycrates.MysteryCrates.onCommand(MysteryCrates.java:2449) ~[?:?]
	at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[spigot-1.8.jar:git-Spigot-330d66b-fe41b01]
	... 14 more