BeTheMob plugin don't work for me!!!

[19:59:47 INFO]: birdmanO_O issued server command: /btm list
[19:59:47 ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'btm'
 in plugin BeTheMob v1.12
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[cra
ftbukkit.jar:git-Bukkit-1.7.2-R0.2-3-g530fcb7-b2979jnks]
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:19
6) ~[craftbukkit.jar:git-Bukkit-1.7.2-R0.2-3-g530fcb7-b2979jnks]
        at org.bukkit.craftbukkit.v1_7_R1.CraftServer.dispatchCommand(CraftServe
r.java:542) ~[craftbukkit.jar:git-Bukkit-1.7.2-R0.2-3-g530fcb7-b2979jnks]
        at net.minecraft.server.v1_7_R1.PlayerConnection.handleCommand(PlayerCon
nection.java:932) [craftbukkit.jar:git-Bukkit-1.7.2-R0.2-3-g530fcb7-b2979jnks]
        at net.minecraft.server.v1_7_R1.PlayerConnection.a(PlayerConnection.java
:814) [craftbukkit.jar:git-Bukkit-1.7.2-R0.2-3-g530fcb7-b2979jnks]
        at net.minecraft.server.v1_7_R1.PacketPlayInChat.a(PacketPlayInChat.java
:28) [craftbukkit.jar:git-Bukkit-1.7.2-R0.2-3-g530fcb7-b2979jnks]
        at net.minecraft.server.v1_7_R1.PacketPlayInChat.handle(PacketPlayInChat
.java:47) [craftbukkit.jar:git-Bukkit-1.7.2-R0.2-3-g530fcb7-b2979jnks]
        at net.minecraft.server.v1_7_R1.NetworkManager.a(NetworkManager.java:146
) [craftbukkit.jar:git-Bukkit-1.7.2-R0.2-3-g530fcb7-b2979jnks]
        at net.minecraft.server.v1_7_R1.ServerConnection.c(SourceFile:134) [craf
tbukkit.jar:git-Bukkit-1.7.2-R0.2-3-g530fcb7-b2979jnks]
        at net.minecraft.server.v1_7_R1.MinecraftServer.u(MinecraftServer.java:6
55) [craftbukkit.jar:git-Bukkit-1.7.2-R0.2-3-g530fcb7-b2979jnks]
        at net.minecraft.server.v1_7_R1.DedicatedServer.u(DedicatedServer.java:2
50) [craftbukkit.jar:git-Bukkit-1.7.2-R0.2-3-g530fcb7-b2979jnks]
        at net.minecraft.server.v1_7_R1.MinecraftServer.t(MinecraftServer.java:5
45) [craftbukkit.jar:git-Bukkit-1.7.2-R0.2-3-g530fcb7-b2979jnks]
        at net.minecraft.server.v1_7_R1.MinecraftServer.run(MinecraftServer.java
:457) [craftbukkit.jar:git-Bukkit-1.7.2-R0.2-3-g530fcb7-b2979jnks]
        at net.minecraft.server.v1_7_R1.ThreadServerApplication.run(SourceFile:6
17) [craftbukkit.jar:git-Bukkit-1.7.2-R0.2-3-g530fcb7-b2979jnks]
Caused by: java.lang.NullPointerException
        at com.lenis0012.bukkit.btm.BeTheMob.getMobList(BeTheMob.java:198) ~[?:?
]
        at com.lenis0012.bukkit.btm.BTMCommand.onCommand(BTMCommand.java:125) ~[
?:?]
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[cra
ftbukkit.jar:git-Bukkit-1.7.2-R0.2-3-g530fcb7-b2979jnks]
        ... 13 more