Bukkit

config file:
name-format: '+name'
text-wrapping: true
censor-list: []
date-format: HH:mm:ss
death-format: '[$prefix+group$suffix&f] +name +message'
join-format: '+name is in de server gekomen.'
quit-format: '+name heeft de server verlaten.'
kick-format: '+name is gekicked door een administrator.'
message-format: '[$prefix+group$suffix&f] +name: +message'
nether-name: +world nether
log-everything: true
update-playerlist: false

server.log with log-everything to true:
2012-05-29 23:18:16 [SEVERE] Could not pass event PlayerChatEvent to Chatter
org.bukkit.event.EventException
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:303)
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:459)
at net.minecraft.server.NetServerHandler.chat(NetServerHandler.java:786)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:764)
at net.minecraft.serverhook.NetServerHandlerProxy.a(NetServerHandlerProxy.java:141)
at net.minecraft.server.Packet3Chat.handle(Packet3Chat.java:34)
at net.minecraft.server.NetworkManager.b(NetworkManager.java:229)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:113)
at net.minecraft.serverhook.NetServerHandlerProxy.a(NetServerHandlerProxy.java:83)
at net.minecraft.server.NetworkListenThread.a(NetworkListenThread.java:78)
at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:558)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:450)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)
Caused by: java.util.UnknownFormatConversionException: Conversion = ' '
at org.bukkit.event.player.PlayerChatEvent.setFormat(PlayerChatEvent.java:82)
at com.dral.Chatter.listeners.ChatterPlayerListener.onPlayerChat(ChatterPlayerListener.java:74)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.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:301)
... 13 more
2012-05-29 23:18:16 [INFO] <AlwaysKevin> Hoi ik ben %
2012-05-29 23:18:20 [INFO] [Admin] AlwaysKevin: Aappje
2012-05-29 23:18:23 [SEVERE] Could not pass event PlayerChatEvent to Chatter
org.bukkit.event.EventException
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:303)
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:459)
at net.minecraft.server.NetServerHandler.chat(NetServerHandler.java:786)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:764)
at net.minecraft.serverhook.NetServerHandlerProxy.a(NetServerHandlerProxy.java:141)
at net.minecraft.server.Packet3Chat.handle(Packet3Chat.java:34)
at net.minecraft.server.NetworkManager.b(NetworkManager.java:229)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:113)
at net.minecraft.serverhook.NetServerHandlerProxy.a(NetServerHandlerProxy.java:83)
at net.minecraft.server.NetworkListenThread.a(NetworkListenThread.java:78)
at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:558)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:450)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)
Caused by: java.util.UnknownFormatConversionException: Conversion = ' '
at org.bukkit.event.player.PlayerChatEvent.setFormat(PlayerChatEvent.java:82)
at com.dral.Chatter.listeners.ChatterPlayerListener.onPlayerChat(ChatterPlayerListener.java:74)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.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:301)
... 13 more

If you use the % in your chat message. The plugin is buggy :)