Well, that was it. I didn't add a "content label". Didn't even know what that was. But I've added it now and tinkered a little bit and my statuses show up just fine now. Thanks.
I get this too. Every time, for every combatant spawner, when I stop the game. If I have 6 combatant spawners, I get this message 6 times when I stop running the game. It doesn't seem to cause any problems really, but it is always there, every time.