2012-12-25 15:33:37 [SEVERE] Could not pass event SignChangeEvent to Appleseed v0.7.3

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 net.minecraft.server.v1_4_6.PlayerConnection.a(PlayerConnection.java:1399)

    at net.minecraft.server.v1_4_6.Packet130UpdateSign.handle(SourceFile:46)

    at net.minecraft.server.v1_4_6.NetworkManager.b(NetworkManager.java:290)

    at net.minecraft.server.v1_4_6.PlayerConnection.d(PlayerConnection.java:112)

    at net.minecraft.server.v1_4_6.ServerConnection.b(SourceFile:39)

    at net.minecraft.server.v1_4_6.DedicatedServerConnection.b(SourceFile:30)

    at net.minecraft.server.v1_4_6.MinecraftServer.r(MinecraftServer.java:598)

    at net.minecraft.server.v1_4_6.DedicatedServer.r(DedicatedServer.java:224)

    at net.minecraft.server.v1_4_6.MinecraftServer.q(MinecraftServer.java:494)

    at net.minecraft.server.v1_4_6.MinecraftServer.run(MinecraftServer.java:427)

    at net.minecraft.server.v1_4_6.ThreadServerApplication.run(SourceFile:849)

Caused by: java.lang.NoClassDefFoundError: org/bukkit/craftbukkit/block/CraftSign

    at redsgreens.Appleseed.AppleseedBlockListener.onSignChange(AppleseedBlockListener.java:32)

    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)

    ... 14 more

Caused by: java.lang.ClassNotFoundException: org.bukkit.craftbukkit.block.CraftSign

    at org.bukkit.plugin.java.PluginClassLoader.findClass0(PluginClassLoader.java:70)

    at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:53)

    at java.lang.ClassLoader.loadClass(Unknown Source)

    at java.lang.ClassLoader.loadClass(Unknown Source)

    ... 20 more