SpectatorPlus error

2015-16-07 17:51:46 [INFO] [SpectatorPlus] Enabling SpectatorPlus v2.1
2015-16-07 17:51:46 [ERROR] Error occurred while enabling SpectatorPlus v2.1 (Is it up to date?)
java.lang.NullPointerException
        at com.pgcraft.spectatorplus.Arena.serialize(Arena.java:88) ~[?:?]
        at org.bukkit.configuration.file.YamlRepresenter$RepresentConfigurationSerializable.representData(YamlRepresenter.java:33) ~[spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at org.yaml.snakeyaml.representer.BaseRepresenter.representData(BaseRepresenter.java:94) ~[spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at org.yaml.snakeyaml.representer.BaseRepresenter.representMapping(BaseRepresenter.java:156) ~[spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at org.yaml.snakeyaml.representer.SafeRepresenter$RepresentMap.representData(SafeRepresenter.java:304) ~[spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at org.bukkit.configuration.file.YamlRepresenter$RepresentConfigurationSection.representData(YamlRepresenter.java:23) ~[spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at org.yaml.snakeyaml.representer.BaseRepresenter.representData(BaseRepresenter.java:94) ~[spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at org.yaml.snakeyaml.representer.BaseRepresenter.representMapping(BaseRepresenter.java:156) ~[spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at org.yaml.snakeyaml.representer.SafeRepresenter$RepresentMap.representData(SafeRepresenter.java:304) ~[spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at org.yaml.snakeyaml.representer.BaseRepresenter.representData(BaseRepresenter.java:94) ~[spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at org.yaml.snakeyaml.representer.BaseRepresenter.represent(BaseRepresenter.java:64) ~[spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at org.yaml.snakeyaml.Yaml.dumpAll(Yaml.java:242) ~[spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at org.yaml.snakeyaml.Yaml.dumpAll(Yaml.java:206) ~[spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at org.yaml.snakeyaml.Yaml.dump(Yaml.java:181) ~[spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at org.bukkit.configuration.file.YamlConfiguration.saveToString(YamlConfiguration.java:40) ~[spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at org.bukkit.configuration.file.FileConfiguration.save(FileConfiguration.java:103) ~[spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at com.pgcraft.spectatorplus.ConfigAccessor.saveConfig(ConfigAccessor.java:80) ~[?:?]
        at com.pgcraft.spectatorplus.SpectatorPlus.setSpectatorMode(SpectatorPlus.java:1229) ~[?:?]
        at com.pgcraft.spectatorplus.SpectatorPlus.reloadConfig(SpectatorPlus.java:1146) ~[?:?]
        at com.pgcraft.spectatorplus.SpectatorPlus.onEnable(SpectatorPlus.java:135) ~[?:?]
        at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:321) ~[spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:340) [spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:405) [spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at org.bukkit.craftbukkit.v1_8_R3.CraftServer.loadPlugin(CraftServer.java:356) [spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at org.bukkit.craftbukkit.v1_8_R3.CraftServer.enablePlugins(CraftServer.java:316) [spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at net.minecraft.server.v1_8_R3.MinecraftServer.s(MinecraftServer.java:414) [spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at net.minecraft.server.v1_8_R3.MinecraftServer.k(MinecraftServer.java:378) [spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at net.minecraft.server.v1_8_R3.MinecraftServer.a(MinecraftServer.java:333) [spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at net.minecraft.server.v1_8_R3.DedicatedServer.init(DedicatedServer.java:263) [spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:524) [spigot-1.8.7-R0.1-SNAPSHOT-latest.jar:git-Spigot-6d16e64-bf4818b]
        at java.lang.Thread.run(Thread.java:745) [?:1.8.0_45]