I have a number that have cropped up, and only now are, sort of, game breaking:
I have the flag missing error on the galactic screen, refered to by Commodore_Areyar above.
My initial install, although working, didnt have working galatic maps or system views. I reinstalled the full 4.90 and patched to 4.91, and the screens now worked, but the error 76 above started. Obviously I can play the game, it just needs a few click throughs on the errors (3 error boxes). I assigned a flag to my empire, the civilians appeat to have one, and the one NPR I have found also has one, both the last without any effort on my part.
The game continued, and I am now encountering another error:
Titled ExectOrders
error 5, invalid procedure call or argument
This pops up in groups of 4, a number of times, perhaps 100 or more. Quite easy to click through, but slows things down. I checked all my taskgroups for conditional orders that might have got messed up, like a ship ordered to join its parent, with no parent assigned, and corrected them all, without solving the problem.
I then went into SM mode to see if there was a dodgy order for an NPR I could see. I have only found one, plus the swarm. I worked out how to see the NPRs planet and screens, and was surprised to find they only had 6 research labs, nothing assigned, the shipyards untooled, and no ships being built. Not so much of a challenge then.
At the outset, to try and avoid the problems of the last game, I set the number of NPRs to 1, with no precursors and no chance of spawning more NPRs, on the basis that any turn interuption would involve me. Later, once I found this a bit dull, I went into SM mode, and activated precursors and NPR chances in new systems again.
The error 5 comes and goes, but a non active NPR is a bit of a game breaker. I will keep the database, but I think I will start a new standard game from 4.91, as I would like a little AI challenge.
Edit: now I have an error 91 NPRpopplanning!