[WARNING] Task of 'MultiInv' generated an exception java.lang.NullPointerException 	at uk.co.tggl.pluckerpluck.multiinv.MultiInvHealthRunnable.run(MultiInvHealthRunnable.java:20) 	at org.bukkit.craftbukkit.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:137) 	at net.minecraft.server.MinecraftServer.h(MinecraftServer.java:439) 	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:374) 	at net.minecraft.server.ThreadServerApplication.run(SourceFile:417)