error

2012-12-09 10:22:15 [SEVERE] Could not load 'plugins/MinetownZombies.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.NoClassDefFoundError: net/minecraft/server/EntityLiving
	at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:154)
	at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:305)
	at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:230)
	at org.bukkit.craftbukkit.v1_4_5.CraftServer.loadPlugins(CraftServer.java:261)
	at org.bukkit.craftbukkit.v1_4_5.CraftServer.<init>(CraftServer.java:239)
	at net.minecraft.server.v1_4_5.ServerConfigurationManagerAbstract.<init>(ServerConfigurationManagerAbstract.java:52)
	at net.minecraft.server.v1_4_5.ServerConfigurationManager.<init>(SourceFile:11)
	at net.minecraft.server.v1_4_5.DedicatedServer.init(DedicatedServer.java:111)
	at net.minecraft.server.v1_4_5.MinecraftServer.run(MinecraftServer.java:402)
	at net.minecraft.server.v1_4_5.ThreadServerApplication.run(SourceFile:856)
Caused by: java.lang.NoClassDefFoundError: net/minecraft/server/EntityLiving
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:264)
	at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:143)
	... 9 more
Caused by: java.lang.ClassNotFoundException: net.minecraft.server.EntityLiving
	at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:34)
	at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:29)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
	... 12 more