2012-02-22 15:25:59 [INFO] Disconnecting Jxxxxx [/xxxxxxx:50373]: Internal server error
2012-02-22 15:25:59 [WARNING] Failed to handle packet: java.lang.IllegalArgumentException: Don't know how to add class net.minecraft.server.EntityMinecart!
java.lang.IllegalArgumentException: Don't know how to add class net.minecraft.server.EntityMinecart!
        at net.minecraft.server.EntityTrackerEntry.b(EntityTrackerEntry.java:429)
        at net.minecraft.server.EntityTrackerEntry.b(EntityTrackerEntry.java:222)
        at net.minecraft.server.EntityTracker.track(EntityTracker.java:38)
        at net.minecraft.server.WorldManager.a(WorldManager.java:16)
        at net.minecraft.server.World.c(World.java:929)
        at net.minecraft.server.WorldServer.c(WorldServer.java:195)
        at net.minecraft.server.World.addEntity(World.java:922)
        at net.minecraft.server.World.addEntity(World.java:873)
        at net.minecraft.server.ServerConfigurationManager.c(ServerConfigurationManager.java:140)
        at net.minecraft.server.NetLoginHandler.b(NetLoginHandler.java:126)
        at net.minecraft.server.NetLoginHandler.a(NetLoginHandler.java:45)
        at net.minecraft.server.NetworkListenThread.a(NetworkListenThread.java:61)
        at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:543)
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:441)
        at net.minecraft.server.ThreadServerApplication.run(SourceFile:465)
2012-02-22 15:26:00 [INFO] Jaliver lost connection: disconnect.endOfStream