I have an error with iconomy

I have this error with Iconomy.
My Mac Osx stats are
Mac OS X
3.06 GHz Intel COre i3
3GB 1333 MHz DDR3

This is the error
09:55:13 [INFO] [iConomy] Enabling iConomy v6.0.8b
09:55:13 [INFO] [iConomy] Default setup file written: Config.yml
09:55:13 [INFO] [iConomy] Default setup file written: Template.yml
09:55:13 [SEVERE] Error occurred while enabling iConomy v6.0.8b (Is it up to date?)
java.lang.NoClassDefFoundError: org/bukkit/util/config/Configuration
at com.iCo6.iConomy.onEnable(iConomy.java:114)
at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:215)
at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:336)
at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:381)
at org.bukkit.craftbukkit.CraftServer.loadPlugin(CraftServer.java:250)
at org.bukkit.craftbukkit.CraftServer.enablePlugins(CraftServer.java:232)
at net.minecraft.server.MinecraftServer.t(MinecraftServer.java:374)
at net.minecraft.server.MinecraftServer.a(MinecraftServer.java:361)
at net.minecraft.server.MinecraftServer.init(MinecraftServer.java:187)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:425)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:490)
Caused by: java.lang.ClassNotFoundException: org.bukkit.util.config.Configuration
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:41)
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:29)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
... 11 more

 

Download the latest version from here:
http://mirror.nexua.org/iConomy/6.0/