CRAFTBOOK-2778 - Reported by Naahzo

tried to make bridge,nothing happens and the console says:

2013-11-09 16:38:49 [SEVERE] Could not pass event SourcedBlockRedstoneEvent to CraftBook v3.7-SNAPSHOT:3311-a992624,master
org.bukkit.event.EventException
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:427)
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:477)
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:462)
at com.sk89q.craftbook.bukkit.MechanicListenerAdapter.handleDirectWireInput(MechanicListenerAdapter.java:335)
at com.sk89q.craftbook.bukkit.MechanicListenerAdapter.handleRedstoneForBlock(MechanicListenerAdapter.java:317)
at com.sk89q.craftbook.bukkit.MechanicListenerAdapter.onBlockRedstoneChange(MechanicListenerAdapter.java:181)
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:425)
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:477)
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:462)
at net.minecraft.server.v1_6_R3.BlockPressurePlateAbstract.b(BlockPressurePlateAbstract.java:102)
at net.minecraft.server.v1_6_R3.BlockPressurePlateAbstract.a(BlockPressurePlateAbstract.java:86)
at net.minecraft.server.v1_6_R3.Entity.D(Entity.java:734)
at net.minecraft.server.v1_6_R3.Entity.move(Entity.java:677)
at net.minecraft.server.v1_6_R3.PlayerConnection.a(PlayerConnection.java:373)
at net.minecraft.server.v1_6_R3.Packet10Flying.handle(SourceFile:136)
at net.minecraft.server.v1_6_R3.NetworkManager.b(NetworkManager.java:296)
at net.minecraft.server.v1_6_R3.PlayerConnection.e(PlayerConnection.java:116)
at net.minecraft.server.v1_6_R3.ServerConnection.b(SourceFile:37)
at net.minecraft.server.v1_6_R3.DedicatedServerConnection.b(SourceFile:30)
at net.minecraft.server.v1_6_R3.MinecraftServer.t(MinecraftServer.java:592)
at net.minecraft.server.v1_6_R3.DedicatedServer.t(DedicatedServer.java:227)
at net.minecraft.server.v1_6_R3.MinecraftServer.s(MinecraftServer.java:488)
at net.minecraft.server.v1_6_R3.MinecraftServer.run(MinecraftServer.java:421)
at net.minecraft.server.v1_6_R3.ThreadServerApplication.run(SourceFile:583)
Caused by: java.lang.NullPointerException
at com.sk89q.craftbook.mech.CommandSigns.onBlockRedstoneChange(CommandSigns.java:67)
at sun.reflect.GeneratedMethodAccessor11.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:425)
... 29 more

using the latest craftbook dev version(3.7.11.2) and bukkit(Build #2918 1.6.4 R-2.0),no other plugins beside worldedit and craftbook
other things(treelopper) are working

Comment by me4502

Please use the latest dev build.