I've gotten this error twice in a row now, once playing on my dedicated server, and once playing single player.
AssertError Failure net\networkserver.d(437) Null nettoclient
This occured while testing a new map. I went in, and made my first move. After hitting end turn, my ships killed the natives and took the planet, then the error appeared. After hitting ok, the game closes. This was when I was testing svgtomap for the first time. I put the .ini into commotion, so it should have had all appropriate fields. The other thing I did differently, is that I added the map to the folder while the server was still running. outside of that I have no clue whats happening.
Oh, just remembered, instead of saying "(AI) Ken" (or whatever the ai name was) it was saying "aisuffix(Ken)". I found that a bit strange before the game crashed.