Chestshop error

10.08 20:58:09 [Server] INFO 	at net.minecraft.server.ThreadServerApplication.run(SourceFile:539)
10.08 20:58:09 [Server] INFO 	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:408)
10.08 20:58:09 [Server] INFO 	at net.minecraft.server.MinecraftServer.p(MinecraftServer.java:476)
10.08 20:58:09 [Server] INFO 	at net.minecraft.server.DedicatedServer.q(DedicatedServer.java:212)
10.08 20:58:09 [Server] INFO 	at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:583)
10.08 20:58:09 [Server] INFO 	at net.minecraft.server.DedicatedServerConnection.b(SourceFile:30)
10.08 20:58:09 [Server] INFO 	at net.minecraft.server.ServerConnection.b(SourceFile:35)
10.08 20:58:09 [Server] INFO 	at net.minecraft.server.NetServerHandler.d(NetServerHandler.java:109)
10.08 20:58:09 [Server] INFO 	at net.minecraft.server.NetworkManager.b(NetworkManager.java:281)
10.08 20:58:09 [Server] INFO 	at net.minecraft.server.Packet130UpdateSign.handle(SourceFile:46)
10.08 20:58:09 [Server] INFO 	at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:1300)
10.08 20:58:09 [Server] INFO 	at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:462)
10.08 20:58:09 [Server] INFO 	at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:477)
10.08 20:58:09 [Server] INFO 	at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
10.08 20:58:09 [Server] INFO 	at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:330)
10.08 20:58:09 [Server] INFO 	at java.lang.reflect.Method.invoke(Method.java:616)
10.08 20:58:09 [Server] INFO 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
10.08 20:58:09 [Server] INFO 	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
10.08 20:58:09 [Server] INFO 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
10.08 20:58:09 [Server] INFO 	at com.Acrobot.ChestShop.Listeners.Block.SignChange.onSignChange(SignChange.java:121)
10.08 20:58:09 [Server] INFO 	at com.Acrobot.ChestShop.ChestShop.callEvent(ChestShop.java:237)
10.08 20:58:09 [Server] INFO 	at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:462)
10.08 20:58:09 [Server] INFO 	at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:477)
10.08 20:58:09 [Server] INFO 	at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
10.08 20:58:09 [Server] INFO 	at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:332)
10.08 20:58:09 [Server] INFO org.bukkit.event.EventException
10.08 20:58:09 [Server] SEVERE Could not pass event ShopCreatedEvent to ChestShop