skywars error 2

[15:34:19] [Server thread/INFO]: MrJonton01 issued server command: /sw start
[15:34:25] [Server thread/WARN]: [SW] Task #1401 for Skywars v1.2.5 generated an exception
java.lang.NullPointerException
    at me.BukkitPVP.Skywars.mapreset.ZoneVolumeMapper.resetEntities(ZoneVolumeMapper.java:218) ~[?:?]
    at me.BukkitPVP.Skywars.mapreset.ArenaVolume.resetEntities(ArenaVolume.java:71) ~[?:?]
    at me.BukkitPVP.Skywars.Game.startGame(Game.java:365) ~[?:?]
    at me.BukkitPVP.Skywars.Game.access$300(Game.java:37) ~[?:?]
    at me.BukkitPVP.Skywars.Game$1.run(Game.java:292) ~[?:?]
    at org.bukkit.craftbukkit.v1_8_R3.scheduler.CraftTask.run(CraftTask.java:71) ~[spigot.jar:git-Spigot-21fe707-e1ebe52]
    at org.bukkit.craftbukkit.v1_8_R3.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:350) [spigot.jar:git-Spigot-21fe707-e1ebe52]
    at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:723) [spigot.jar:git-Spigot-21fe707-e1ebe52]
    at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:374) [spigot.jar:git-Spigot-21fe707-e1ebe52]
    at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:654) [spigot.jar:git-Spigot-21fe707-e1ebe52]
    at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:557) [spigot.jar:git-Spigot-21fe707-e1ebe52]
    at java.lang.Thread.run(Unknown Source) [?:1.8.0_66]