This error happen at startup when I started the server :

[22:17:52] [Server thread/WARN]: [PlayTime] Task #4 for Playtime v1.4.5 generated an exception
java.lang.ArrayIndexOutOfBoundsException: -1
at java.util.ArrayList.elementData(Unknown Source) ~[?:1.8.0_66]
at java.util.ArrayList.get(Unknown Source) ~[?:1.8.0_66]
at com.rogue.playtime.update.UpdateRunnable.getJSON(UpdateHandler.java:357) ~[?:?]
at com.rogue.playtime.update.UpdateRunnable.run(UpdateHandler.java:179) ~[?:?]
at org.bukkit.craftbukkit.v1_8_R3.scheduler.CraftTask.run(CraftTask.java:71) ~[spigot-1.8.8.jar:git-Spigot-76236cb-c373061]
at org.bukkit.craftbukkit.v1_8_R3.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:350) [spigot-1.8.8.jar:git-Spigot-76236cb-c373061]
at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:723) [spigot-1.8.8.jar:git-Spigot-76236cb-c373061]
at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:374) [spigot-1.8.8.jar:git-Spigot-76236cb-c373061]
at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:654) [spigot-1.8.8.jar:git-Spigot-76236cb-c373061]
at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:557) [spigot-1.8.8.jar:git-Spigot-76236cb-c373061]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_66]