wrongly packed?

I get this error when unpacking it for the first time:
Got an error with nat.Hikari: java.lang.ClassNotFoundException: nat/Hikari : Unsupported major.minor version 51.0
And so this bot does not get any valid battles.

Sounds like Nat compiled this with a newer version of Java than you're using GrubbmGait

Just checked "major.minor version 51.0" specifically, and it means Nat compiled with Java 7... tsk tsk... :P

Argh...... Always forget to set compatibility to Java 5 now that I have only Java 7 installed. (My old computer default to Java 5 JRE, so it compile with Java 5 compat by default) Anyway, should work now. Thanks!

I use Java 1.6.0_29, that should be new enough. When compiling my own bots, I still have turned Java 5 compatibility on.