Błąd worldBorder

Witam, mam pewien problem, ponieważ co sekundę w konsoli wyskakuje mi taki błąd:

[12:29:54 WARN]: [WorldBorder] Task #18 for WorldBorder v1.8.6 generated an exception
java.lang.NoSuchMethodError: org.bukkit.Server.getOnlinePlayers()Ljava/util/Collection;
        at com.wimbli.WorldBorder.BorderCheckTask.run(BorderCheckTask.java:31) ~[?:?]
        at org.bukkit.craftbukkit.v1_7_R1.scheduler.CraftTask.run(CraftTask.java:53) ~[minecraft_server.jar:git-Bukkit-1.7.2-R0.3-2-g85f5776-b3023jnks]
        at org.bukkit.craftbukkit.v1_7_R1.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:345) [minecraft_server.jar:git-Bukkit-1.7.2-R0.3-2-g85f5776-b3023jnks]
        at net.minecraft.server.v1_7_R1.MinecraftServer.u(MinecraftServer.java:587) [minecraft_server.jar:git-Bukkit-1.7.2-R0.3-2-g85f5776-b3023jnks]
        at net.minecraft.server.v1_7_R1.DedicatedServer.u(DedicatedServer.java:250) [minecraft_server.jar:git-Bukkit-1.7.2-R0.3-2-g85f5776-b3023jnks]
        at net.minecraft.server.v1_7_R1.MinecraftServer.t(MinecraftServer.java:545) [minecraft_server.jar:git-Bukkit-1.7.2-R0.3-2-g85f5776-b3023jnks]
        at net.minecraft.server.v1_7_R1.MinecraftServer.run(MinecraftServer.java:457) [minecraft_server.jar:git-Bukkit-1.7.2-R0.3-2-g85f5776-b3023jnks]
        at net.minecraft.server.v1_7_R1.ThreadServerApplication.run(SourceFile:617) [minecraft_server.jar:git-Bukkit-1.7.2-R0.3-2-g85f5776-b3023jnks]