Far as i can see everything works fine except i get this error sometimes in the console, its so big it floods it. how do i fix this?

2012-04-24 22:55:48 [SEVERE] Could not pass event BlockPlaceEvent to PreciousStones
org.bukkit.event.EventException
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:303)
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:459)
at org.bukkit.craftbukkit.event.CraftEventFactory.callBlockPlaceEvent(CraftEventFactory.java:98)
at net.minecraft.server.ItemBlock.interactWith(ItemBlock.java:71)
at net.minecraft.server.ItemStack.placeItem(ItemStack.java:83)
at net.minecraft.server.ItemInWorldManager.interact(ItemInWorldManager.java:303)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:636)
at net.minecraft.server.Packet15Place.handle(SourceFile:39)
at net.minecraft.server.NetworkManager.b(NetworkManager.java:229)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:113)
at net.minecraft.server.NetworkListenThread.a(NetworkListenThread.java:78)
at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:551)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:449)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)
Caused by: java.lang.NullPointerException
at net.sacredlabyrinth.Phaed.PreciousStones.managers.ForceFieldManager.isAllowed(ForceFieldManager.java:1149)
at net.sacredlabyrinth.Phaed.PreciousStones.managers.ForceFieldManager.isApplyToAllowed(ForceFieldManager.java:1100)
at net.sacredlabyrinth.Phaed.PreciousStones.listeners.PSBlockListener.onBlockPlace(PSBlockListener.java:884)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:301)
... 14 more
2012-04-24 22:55:51 [SEVERE] Could not pass event BlockPlaceEvent to PreciousStones
org.bukkit.event.EventException
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:303)
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:459)
at org.bukkit.craftbukkit.event.CraftEventFactory.callBlockPlaceEvent(CraftEventFactory.java:98)
at net.minecraft.server.ItemBlock.interactWith(ItemBlock.java:71)
at net.minecraft.server.ItemStack.placeItem(ItemStack.java:83)
at net.minecraft.server.ItemInWorldManager.interact(ItemInWorldManager.java:303)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:636)
at net.minecraft.server.Packet15Place.handle(SourceFile:39)
at net.minecraft.server.NetworkManager.b(NetworkManager.java:229)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:113)
at net.minecraft.server.NetworkListenThread.a(NetworkListenThread.java:78)
at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:551)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:449)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)
Caused by: java.lang.NullPointerException
at net.sacredlabyrinth.Phaed.PreciousStones.managers.ForceFieldManager.isAllowed(ForceFieldManager.java:1149)
at net.sacredlabyrinth.Phaed.PreciousStones.managers.ForceFieldManager.isApplyToAllowed(ForceFieldManager.java:1100)
at net.sacredlabyrinth.Phaed.PreciousStones.listeners.PSBlockListener.onBlockPlace(PSBlockListener.java:899)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:301)
... 14 more
2012-04-24 22:55:55 [SEVERE] Could not pass event BlockPlaceEvent to PreciousStones
org.bukkit.event.EventException
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:303)
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:459)
at org.bukkit.craftbukkit.event.CraftEventFactory.callBlockPlaceEvent(CraftEventFactory.java:98)
at net.minecraft.server.ItemBlock.interactWith(ItemBlock.java:71)
at net.minecraft.server.ItemStack.placeItem(ItemStack.java:83)
at net.minecraft.server.ItemInWorldManager.interact(ItemInWorldManager.java:303)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:636)
at net.minecraft.server.Packet15Place.handle(SourceFile:39)
at net.minecraft.server.NetworkManager.b(NetworkManager.java:229)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:113)
at net.minecraft.server.NetworkListenThread.a(NetworkListenThread.java:78)
at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:551)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:449)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)
Caused by: java.lang.NullPointerException
at net.sacredlabyrinth.Phaed.PreciousStones.managers.ForceFieldManager.isAllowed(ForceFieldManager.java:1149)
at net.sacredlabyrinth.Phaed.PreciousStones.managers.ForceFieldManager.isApplyToAllowed(ForceFieldManager.java:1100)
at net.sacredlabyrinth.Phaed.PreciousStones.listeners.PSBlockListener.onBlockPlace(PSBlockListener.java:869)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:301)
... 14 more
2012-04-24 22:55:56 [SEVERE] Could not pass event BlockPlaceEvent to PreciousStones
org.bukkit.event.EventException
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:303)
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:459)
at org.bukkit.craftbukkit.event.CraftEventFactory.callBlockPlaceEvent(CraftEventFactory.java:98)
at net.minecraft.server.ItemBlock.interactWith(ItemBlock.java:71)
at net.minecraft.server.ItemStack.placeItem(ItemStack.java:83)
at net.minecraft.server.ItemInWorldManager.interact(ItemInWorldManager.java:303)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:636)
at net.minecraft.server.Packet15Place.handle(SourceFile:39)
at net.minecraft.server.NetworkManager.b(NetworkManager.java:229)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:113)
at net.minecraft.server.NetworkListenThread.a(NetworkListenThread.java:78)
at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:551)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:449)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)
Caused by: java.lang.NullPointerException
at net.sacredlabyrinth.Phaed.PreciousStones.managers.ForceFieldManager.isAllowed(ForceFieldManager.java:1149)
at net.sacredlabyrinth.Phaed.PreciousStones.managers.ForceFieldManager.isApplyToAllowed(ForceFieldManager.java:1100)
at net.sacredlabyrinth.Phaed.PreciousStones.listeners.PSBlockListener.onBlockPlace(PSBlockListener.java:869)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:301)
... 14 more
2012-04-24 22:56:02 [SEVERE] Could not pass event BlockPlaceEvent to PreciousStones
org.bukkit.event.EventException
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:303)
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:459)
at org.bukkit.craftbukkit.event.CraftEventFactory.callBlockPlaceEvent(CraftEventFactory.java:98)
at net.minecraft.server.ItemBlock.interactWith(ItemBlock.java:71)
at net.minecraft.server.ItemStack.placeItem(ItemStack.java:83)
at net.minecraft.server.ItemInWorldManager.interact(ItemInWorldManager.java:303)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:636)
at net.minecraft.server.Packet15Place.handle(SourceFile:39)
at net.minecraft.server.NetworkManager.b(NetworkManager.java:229)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:113)
at net.minecraft.server.NetworkListenThread.a(NetworkListenThread.java:78)
at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:551)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:449)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)
Caused by: java.lang.NullPointerException
at net.sacredlabyrinth.Phaed.PreciousStones.managers.ForceFieldManager.isAllowed(ForceFieldManager.java:1149)
at net.sacredlabyrinth.Phaed.PreciousStones.managers.ForceFieldManager.isApplyToAllowed(ForceFieldManager.java:1100)
at net.sacredlabyrinth.Phaed.PreciousStones.listeners.PSBlockListener.onBlockPlace(PSBlockListener.java:884)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:301)
... 14 more

fixed