PA Nullpointer Exception

at fy.run(ThreadMinecraftServer.java:16)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:744)
at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:857)
at ho.r(DedicatedServer.java:309)
at net.minecraft.server.MinecraftServer.r(MinecraftServer.java:899)
at org.bukkit.craftbukkit.v1_4_R1.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:344)
at org.bukkit.craftbukkit.v1_4_R1.scheduler.CraftTask.run(CraftTask.java:53)
at edgruberman.bukkit.playeractivity.IdleChecker.run(Unknown Source)
at edgruberman.bukkit.playeractivity.IdlePublisher.publish(Unknown Source)
at java.util.Observable.notifyObservers(Observable.java:159)
at edgruberman.bukkit.playeractivity.consumers.IdleKick.update(Unknown Source)
java.lang.NullPointerException

22:16:28 [WARNUNG] [PlayerActivity] Task #74896 for PlayerActivity v4.2.0 generated an exception
2013-04-03 22:14:27 [WARNING] [IC2] removing cpw.mods.compactsolars.TileEntityCompactSolar@3a588bdf from the EnergyNet failed, already removed: true
2013-04-03 22:14:19 [WARNING] [IC2] removing cpw.mods.compactsolars.TileEntityCompactSolar@6f648a33 from the EnergyNet failed, already removed: true
>2013-04-03 22:14:17 [WARNING] [IC2] removing