Horses Not Spawning

Code:

20:36:30 [SEVERE] com.sk89q.minecraft.util.commands.WrappedCommandException: jav
a.lang.IllegalArgumentException: Cannot spawn an entity for org.bukkit.entity.Ho
rse
20:36:30 [SEVERE]      at com.sk89q.minecraft.util.commands.CommandsManager.inv
okeMethod(CommandsManager.java:543)
20:36:30 [SEVERE]      at com.sk89q.minecraft.util.commands.CommandsManager.exe
cuteMethod(CommandsManager.java:520)
20:36:30 [SEVERE]      at com.sk89q.minecraft.util.commands.CommandsManager.exe
cute(CommandsManager.java:409)
20:36:30 [SEVERE]      at com.zachsthings.libcomponents.bukkit.BukkitComponent.
onCommand(BukkitComponent.java:80)
20:36:30 [SEVERE]      at com.sk89q.bukkit.util.DynamicPluginCommand.execute(Dy
namicPluginCommand.java:52)
20:36:30 [SEVERE]      at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCo
mmandMap.java:189)
20:36:30 [SEVERE]      at org.bukkit.craftbukkit.v1_6_R1.CraftServer.dispatchCo
mmand(CraftServer.java:523)
20:36:30 [SEVERE]      at net.minecraft.server.v1_6_R1.PlayerConnection.handleC
ommand(PlayerConnection.java:983)
20:36:30 [SEVERE]      at net.minecraft.server.v1_6_R1.PlayerConnection.chat(Pl
ayerConnection.java:901)
20:36:30 [SEVERE]      at net.minecraft.server.v1_6_R1.PlayerConnection.a(Playe
rConnection.java:858)
20:36:30 [SEVERE]      at net.minecraft.server.v1_6_R1.Packet3Chat.handle(Sourc
eFile:49)
20:36:30 [SEVERE]      at net.minecraft.server.v1_6_R1.NetworkManager.b(Network
Manager.java:293)
20:36:30 [SEVERE]      at net.minecraft.server.v1_6_R1.PlayerConnection.d(Playe
rConnection.java:118)
20:36:30 [SEVERE]      at net.minecraft.server.v1_6_R1.ServerConnection.b(Sourc
eFile:37)
20:36:30 [SEVERE]      at net.minecraft.server.v1_6_R1.DedicatedServerConnectio
n.b(SourceFile:30)
20:36:30 [SEVERE]      at net.minecraft.server.v1_6_R1.MinecraftServer.t(Minecr
aftServer.java:590)
20:36:30 [SEVERE]      at net.minecraft.server.v1_6_R1.DedicatedServer.t(Dedica
tedServer.java:226)
20:36:30 [SEVERE]      at net.minecraft.server.v1_6_R1.MinecraftServer.s(Minecr
aftServer.java:486)
20:36:30 [SEVERE]      at net.minecraft.server.v1_6_R1.MinecraftServer.run(Mine
craftServer.java:419)
20:36:30 [SEVERE]      at net.minecraft.server.v1_6_R1.ThreadServerApplication.
run(SourceFile:582)
20:36:30 [SEVERE] Caused by: java.lang.IllegalArgumentException: Cannot spawn an
entity for org.bukkit.entity.Horse
20:36:30 [SEVERE]      at org.bukkit.craftbukkit.v1_6_R1.CraftWorld.spawn(Craft
World.java:1022)
20:36:30 [SEVERE]      at org.bukkit.craftbukkit.v1_6_R1.CraftWorld.spawn(Craft
World.java:792)
20:36:30 [SEVERE]      at com.sk89q.commandbook.FunComponent.spawn(FunComponent
.java:52)
20:36:30 [SEVERE]      at com.sk89q.commandbook.FunComponent$Commands.spawnMob(
FunComponent.java:200)
20:36:30 [SEVERE]      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native M
ethod)
20:36:30 [SEVERE]      at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown S
ource)
20:36:30 [SEVERE]      at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unkno
wn Source)
20:36:30 [SEVERE]      at java.lang.reflect.Method.invoke(Unknown Source)
20:36:30 [SEVERE]      at com.sk89q.minecraft.util.commands.CommandsManager.inv
okeMethod(CommandsManager.java:533)
20:36:30 [SEVERE]      ... 19 more

This happens every time I use the /spawnmob horse. the game tells me to look at the console and I get this text. What do I do?

 

We do not support dev builds of any version.

 

That's right, sorry. I completely forgot I was running a dev version.

 

the error here is caused by bukkit API needing updating foxtara