[SEVERE] Could not load 'plugins\Hacks.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.NoClassDefFoundError: net/minecraft/server/v1_5_R2/Entity
	at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:184)
	at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:305)
	at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:230)
	at org.bukkit.craftbukkit.v1_5_R1.CraftServer.loadPlugins(CraftServer.java:239)
	at org.bukkit.craftbukkit.v1_5_R1.CraftServer.reload(CraftServer.java:594)
	at org.bukkit.Bukkit.reload(Bukkit.java:184)
	at org.bukkit.command.defaults.ReloadCommand.execute(ReloadCommand.java:23)
	at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:186)
	at org.bukkit.craftbukkit.v1_5_R1.CraftServer.dispatchCommand(CraftServer.java:514)
	at org.bukkit.craftbukkit.v1_5_R1.CraftServer.dispatchServerCommand(CraftServer.java:506)
	at net.minecraft.server.v1_5_R1.DedicatedServer.am(DedicatedServer.java:261)
	at net.minecraft.server.v1_5_R1.DedicatedServer.r(DedicatedServer.java:226)
	at net.minecraft.server.v1_5_R1.MinecraftServer.q(MinecraftServer.java:476)
	at net.minecraft.server.v1_5_R1.MinecraftServer.run(MinecraftServer.java:409)
	at net.minecraft.server.v1_5_R1.ThreadServerApplication.run(SourceFile:573)
Caused by: java.lang.NoClassDefFoundError: net/minecraft/server/v1_5_R2/Entity
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Unknown Source)
	at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:173)
	... 14 more
Caused by: java.lang.ClassNotFoundException: net.minecraft.server.v1_5_R2.Entity
	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)
	... 17 more