Error message

[00:44:08] [Server thread/INFO]: Greenadine issued server command: /ws check world
[00:44:08] [Server thread/ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'ws' in plugin WorldSpawns_mineCaste v1.0
	at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:140) ~[craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at org.bukkit.craftbukkit.v1_9_R2.CraftServer.dispatchCommand(CraftServer.java:625) ~[craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at net.minecraft.server.v1_9_R2.PlayerConnection.handleCommand(PlayerConnection.java:1297) [craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at net.minecraft.server.v1_9_R2.PlayerConnection.a(PlayerConnection.java:1157) [craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at net.minecraft.server.v1_9_R2.PacketPlayInChat.a(SourceFile:37) [craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at net.minecraft.server.v1_9_R2.PacketPlayInChat.a(SourceFile:9) [craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at net.minecraft.server.v1_9_R2.PlayerConnectionUtils$1.run(SourceFile:13) [craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [?:1.8.0_92]
	at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_92]
	at net.minecraft.server.v1_9_R2.SystemUtils.a(SourceFile:45) [craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at net.minecraft.server.v1_9_R2.MinecraftServer.D(MinecraftServer.java:683) [craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at net.minecraft.server.v1_9_R2.DedicatedServer.D(DedicatedServer.java:360) [craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at net.minecraft.server.v1_9_R2.MinecraftServer.C(MinecraftServer.java:639) [craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at net.minecraft.server.v1_9_R2.MinecraftServer.run(MinecraftServer.java:543) [craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at java.lang.Thread.run(Unknown Source) [?:1.8.0_92]
Caused by: java.lang.NullPointerException
	at org.bukkit.Location.getBlock(Location.java:87) ~[craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at me.greenadine.worldspawns.CommandWorldspawns.onCommand(CommandWorldspawns.java:118) ~[?:?]
	at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	... 15 more
[00:44:11] [Server thread/INFO]: Greenadine issued server command: /setpsawn
[00:44:12] [Server thread/INFO]: Greenadine issued server command: /setspawn
[00:44:14] [Server thread/INFO]: Greenadine issued server command: /ws check world
[00:44:14] [Server thread/ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'ws' in plugin WorldSpawns_mineCaste v1.0
	at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:140) ~[craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at org.bukkit.craftbukkit.v1_9_R2.CraftServer.dispatchCommand(CraftServer.java:625) ~[craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at net.minecraft.server.v1_9_R2.PlayerConnection.handleCommand(PlayerConnection.java:1297) [craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at net.minecraft.server.v1_9_R2.PlayerConnection.a(PlayerConnection.java:1157) [craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at net.minecraft.server.v1_9_R2.PacketPlayInChat.a(SourceFile:37) [craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at net.minecraft.server.v1_9_R2.PacketPlayInChat.a(SourceFile:9) [craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at net.minecraft.server.v1_9_R2.PlayerConnectionUtils$1.run(SourceFile:13) [craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [?:1.8.0_92]
	at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_92]
	at net.minecraft.server.v1_9_R2.SystemUtils.a(SourceFile:45) [craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at net.minecraft.server.v1_9_R2.MinecraftServer.D(MinecraftServer.java:683) [craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at net.minecraft.server.v1_9_R2.DedicatedServer.D(DedicatedServer.java:360) [craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at net.minecraft.server.v1_9_R2.MinecraftServer.C(MinecraftServer.java:639) [craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at net.minecraft.server.v1_9_R2.MinecraftServer.run(MinecraftServer.java:543) [craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at java.lang.Thread.run(Unknown Source) [?:1.8.0_92]
Caused by: java.lang.NullPointerException
	at org.bukkit.Location.getBlock(Location.java:87) ~[craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	at me.greenadine.worldspawns.CommandWorldspawns.onCommand(CommandWorldspawns.java:118) ~[?:?]
	at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[craftbukkit-1.9.4.jar:git-Bukkit-0cd0397]
	... 15 more
[00:59:06] [pool-3-thread-22/WARN]: Exception in thread "pool-3-thread-22"
[00:59:06] [pool-3-thread-22/WARN]: org.apache.commons.lang.UnhandledException: Plugin GroupManager vPre2.14.1.3 FINAL (Phoenix) generated an exception while executing task 13
	at org.bukkit.craftbukkit.v1_9_R2.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:56)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NoSuchMethodError: org.bukkit.Server.getOnlinePlayers()[Lorg/bukkit/entity/Player;
	at org.anjocaido.groupmanager.metrics.Metrics.postPlugin(Metrics.java:335)
	at org.anjocaido.groupmanager.metrics.Metrics.access$400(Metrics.java:57)
	at org.anjocaido.groupmanager.metrics.Metrics$1.run(Metrics.java:223)
	at org.bukkit.craftbukkit.v1_9_R2.scheduler.CraftTask.run(CraftTask.java:53)
	at org.bukkit.craftbukkit.v1_9_R2.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:53)
	... 3 more