User blog:Lueraw/Tekkit 3.1.3 server problems, can some advise please?

This server has been running fine and no special machines such as the "rotary macerator" were crafted. This is the message I'm getting.

20:33:22 [WARNING] Failed to handle packet: java.lang.NullPointerException java.lang.NullPointerException at net.minecraft.server.ServerConfigurationManager.attemptLogin(ServerCo nfigurationManager.java:213) at net.minecraft.server.NetLoginHandler.b(NetLoginHandler.java:111) at net.minecraft.server.NetLoginHandler.a(NetLoginHandler.java:44) at net.minecraft.server.NetworkListenThread.a(NetworkListenThread.java:6 5) at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:569) at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:457) at net.minecraft.server.ThreadServerApplication.run(SourceFile:492) >