Same issue with the Eastern Front mod. The fatal AI error when playing against the Russian faction within the beginning stages of the game.
Out of 3 players in the multiplayer game, all have had the AI error once each in three consecutive games. While the other 2 are notified waiting for "[playername] # seconds", the effected player is notified in the bottom of the screen "Fatal AI error".
We have recently reinstalled the version 1.7.0.1 and played Eastern Front 5-6 times online without the fatal AI error occurring. To confirm if it was the version 1.7.2.0, we downloaded the updates to from 1.7.0.1 to 1.7.2.0 via Launcher. Then we were able to play one game successfully in the map "Drekplaats" and completed the game without errors. Then the next two times we played the error came back again in the map "EF Leningrad" and "Steel Pact". Each time we played the Fatal AI error reoccurred.
As mentioned already this appears to be consistent with the Russian faction as the AI.
I notice that when you get the fatal error and the game stops that you can use the Pause button on your keyboard to continue the game. ;)
I hope this info can help a little bit for the developers.
This appears to be similar to using "menu" then "resume" When playing single player against or with a Russian faction. From my experience, the game continues to play again, but for the remainder of the game with this in mind, the Russian faction's AI appears to stop functioning and there are no active unit movements. Although still attacking when enemy units are in range.
I am providing a scarlog and the replay of the last game played with the Fatal AI error. I hope this information is useful in narrowing down the source of the issue.