PingReply Error 1.5.2

[SEVERE] Could not pass event PlayerCommandPreprocessEvent to PingReply v1.1
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.TimedRegisteredListener.callEvent(TimedRegisteredListener.java:39)
    at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:479)
    at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:464)
    at net.minecraft.server.v1_5_R3.PlayerConnection.handleCommand(PlayerConnection.java:970)
    at net.minecraft.server.v1_5_R3.PlayerConnection.chat(PlayerConnection.java:895)
    at net.minecraft.server.v1_5_R3.PlayerConnection.a(PlayerConnection.java:840)
    at net.minecraft.server.v1_5_R3.Packet3Chat.handle(Packet3Chat.java:44)
    at org.spigotmc.netty.NettyNetworkManager.b(NettyNetworkManager.java:186)
    at net.minecraft.server.v1_5_R3.PlayerConnection.d(PlayerConnection.java:109)
    at net.minecraft.server.v1_5_R3.ServerConnection.b(SourceFile:35)
    at org.spigotmc.MultiplexingServerConnection.b(MultiplexingServerConnection.java:72)
    at net.minecraft.server.v1_5_R3.MinecraftServer.r(MinecraftServer.java:583)
    at net.minecraft.server.v1_5_R3.DedicatedServer.r(DedicatedServer.java:224)
    at net.minecraft.server.v1_5_R3.MinecraftServer.q(MinecraftServer.java:472)
    at net.minecraft.server.v1_5_R3.MinecraftServer.run(MinecraftServer.java:404)
    at net.minecraft.server.v1_5_R3.ThreadServerApplication.run(SourceFile:573)
Caused by: org.bukkit.command.CommandException: Unhandled exception executing command 'ping1' in plugin PingReply v1.1
    at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46)
    at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:189)
    at org.bukkit.craftbukkit.v1_5_R3.CraftServer.dispatchCommand(CraftServer.java:547)
    at org.bukkit.craftbukkit.v1_5_R3.entity.CraftPlayer.performCommand(CraftPlayer.java:241)
    at com.tschagg.PingReply.tschaggplugin_listener.onPlayerCommandPreprocess(tschaggplugin_listener.java:23)
    at sun.reflect.GeneratedMethodAccessor117.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)
    ... 17 more
Caused by: java.lang.NoClassDefFoundError: org/bukkit/craftbukkit/v1_5_R2/entity/CraftPlayer
    at com.tschagg.PingReply.tschaggplugin_main.getPing(tschaggplugin_main.java:105)
    at com.tschagg.PingReply.tschaggplugin_main.onCommand(tschaggplugin_main.java:66)
    at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44)
    ... 25 more
Caused by: java.lang.ClassNotFoundException: org.bukkit.craftbukkit.v1_5_R2.entity.CraftPlayer
    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)
    ... 28 more