CraftBook HeadDrops Error

[03:16:10] [Server thread/ERROR]: Could not pass event BlockBreakEvent to CraftBook v3.8-SNAPSHOT:3779-116355d,master
org.bukkit.event.EventException
	at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:302) ~[spigot-1.7.10-R0.1-1649-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
	at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[spigot-1.7.10-R0.1-1649-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
	at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:509) [spigot-1.7.10-R0.1-1649-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
	at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:494) [spigot-1.7.10-R0.1-1649-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
	at net.minecraft.server.v1_7_R4.PlayerInteractManager.breakBlock(PlayerInteractManager.java:264) [spigot-1.7.10-R0.1-1649-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
	at net.minecraft.server.v1_7_R4.PlayerInteractManager.a(PlayerInteractManager.java:192) [spigot-1.7.10-R0.1-1649-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
	at net.minecraft.server.v1_7_R4.PlayerConnection.a(PlayerConnection.java:565) [spigot-1.7.10-R0.1-1649-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
	at net.minecraft.server.v1_7_R4.PacketPlayInBlockDig.a(PacketPlayInBlockDig.java:41) [spigot-1.7.10-R0.1-1649-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
	at net.minecraft.server.v1_7_R4.PacketPlayInBlockDig.handle(PacketPlayInBlockDig.java:65) [spigot-1.7.10-R0.1-1649-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
	at net.minecraft.server.v1_7_R4.NetworkManager.a(NetworkManager.java:186) [spigot-1.7.10-R0.1-1649-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
	at net.minecraft.server.v1_7_R4.ServerConnection.c(ServerConnection.java:81) [spigot-1.7.10-R0.1-1649-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
	at net.minecraft.server.v1_7_R4.MinecraftServer.v(MinecraftServer.java:734) [spigot-1.7.10-R0.1-1649-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
	at net.minecraft.server.v1_7_R4.DedicatedServer.v(DedicatedServer.java:289) [spigot-1.7.10-R0.1-1649-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
	at net.minecraft.server.v1_7_R4.MinecraftServer.u(MinecraftServer.java:584) [spigot-1.7.10-R0.1-1649-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
	at net.minecraft.server.v1_7_R4.MinecraftServer.run(MinecraftServer.java:490) [spigot-1.7.10-R0.1-1649-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
	at net.minecraft.server.v1_7_R4.ThreadServerApplication.run(SourceFile:628) [spigot-1.7.10-R0.1-1649-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
Caused by: java.lang.NoSuchMethodError: org.bukkit.block.Skull.getPlayer()Lorg/bukkit/OfflinePlayer;
	at com.sk89q.craftbook.mech.HeadDrops.onBlockBreak(HeadDrops.java:166) ~[?:?]
	at sun.reflect.GeneratedMethodAccessor242.invoke(Unknown Source) ~[?:?]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_25]
	at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_25]
	at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:298) ~[spigot-1.7.10-R0.1-1649-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
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