Sumo Error

[13:57:01] [Server thread/INFO]: [Sumo] Enabling Sumo v1.0
[13:57:01] [Server thread/ERROR]: Error occurred while enabling Sumo v1.0 (Is it up to date?)
java.lang.IllegalArgumentException: bound must be positive
    at java.util.Random.nextInt(Unknown Source) ~[?:1.8.0_45]
    at tfw.Sumo.Game.randomMap(Game.java:106) ~[?:?]
    at tfw.Sumo.Main.onEnable(Main.java:68) ~[?:?]
    at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:321) ~[spigot.jar:git-Spigot-2f787bd-ea28011]
    at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:335) [spigot.jar:git-Spigot-2f787bd-ea28011]
    at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:405) [spigot.jar:git-Spigot-2f787bd-ea28011]
    at org.bukkit.craftbukkit.v1_8_R2.CraftServer.loadPlugin(CraftServer.java:356) [spigot.jar:git-Spigot-2f787bd-ea28011]
    at org.bukkit.craftbukkit.v1_8_R2.CraftServer.enablePlugins(CraftServer.java:316) [spigot.jar:git-Spigot-2f787bd-ea28011]
    at net.minecraft.server.v1_8_R2.MinecraftServer.r(MinecraftServer.java:416) [spigot.jar:git-Spigot-2f787bd-ea28011]
    at net.minecraft.server.v1_8_R2.MinecraftServer.k(MinecraftServer.java:382) [spigot.jar:git-Spigot-2f787bd-ea28011]
    at net.minecraft.server.v1_8_R2.MinecraftServer.a(MinecraftServer.java:337) [spigot.jar:git-Spigot-2f787bd-ea28011]
    at net.minecraft.server.v1_8_R2.DedicatedServer.init(DedicatedServer.java:257) [spigot.jar:git-Spigot-2f787bd-ea28011]
    at net.minecraft.server.v1_8_R2.MinecraftServer.run(MinecraftServer.java:522) [spigot.jar:git-Spigot-2f787bd-ea28011]
    at java.lang.Thread.run(Unknown Source) [?:1.8.0_45]