Bukkit

2012-03-11 07:09:43 [SEVERE] Could not load 'plugins\showcase-dev-SNAPSHOT.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.NoClassDefFoundError: org/bukkit/event/player/PlayerListener
    at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:148)
    at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:287)
    at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:211)
    at org.bukkit.craftbukkit.CraftServer.loadPlugins(CraftServer.java:207)
    at org.bukkit.craftbukkit.CraftServer.<init>(CraftServer.java:183)
    at net.minecraft.server.ServerConfigurationManager.<init>(ServerConfigurationManager.java:56)
    at net.minecraft.server.MinecraftServer.init(MinecraftServer.java:156)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:425)
    at net.minecraft.server.ThreadServerApplication.run(SourceFile:490)
Caused by: java.lang.NoClassDefFoundError: org/bukkit/event/player/PlayerListener
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:791)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
    at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    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:423)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
    at com.narrowtux.showcase.Showcase.<init>(Showcase.java:76)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:525)
    at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:144)
    ... 8 more
Caused by: java.lang.ClassNotFoundException: org.bukkit.event.player.PlayerListener
    at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    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:423)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
    ... 27 more

same problem let me know if you get the fix