Thermos Staktrace #1

[16:21:53] [Server thread/ERROR]: Encountered an unexpected exception
java.lang.NoSuchMethodError: net.minecraft.server.management.PlayerManager.<init>(Lnet/minecraft/world/WorldServer;I)V
    at net.minecraft.world.WorldServer.<init>(WorldServer.java:168) ~[mt.class:?]
    at net.minecraft.server.MinecraftServer.func_71247_a(MinecraftServer.java:369) ~[MinecraftServer.class:?]
    at net.minecraft.server.dedicated.DedicatedServer.func_71197_b(DedicatedServer.java:336) ~[lt.class:?]
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:633) [MinecraftServer.class:?]
    at java.lang.Thread.run(Unknown Source) [?:1.8.0_71]
[16:21:53] [Server thread/ERROR]: This crash report has been saved to: C:\Users\TriiNoxYs\Desktop\Thermos\.\crash-reports\crash-2016-04-03_16.21.53-server.txt