Sorry, no solution, as I have the exact same problem.
I have reloaded the gamesave - no fix.
I have reloaded the earliest gamesave - no fix.
I have restarted the game entirely - no fix.
Reseting gamescript "Renewed World Disorder" - no fix.
Tried to uncheck the Pause on game load and a new save - no fix.
Console command "unpause" = "Game cannot be unpause manually; disable pause_on_join/min_active_clients."
("min_active_clients" not a valid command, probably a multiplayer specific thing.)
Setting "pause_on_join" to "0" and then run command "unpause" gets the game running again, even though I get the "...cannot be unpaused..." error in console.
But saving and reloading the save again, I'm back on square one again... And the above trick doesn't work anymore.
(I've tried to recreate the original conditions to no avail)
Been trying to solve this while writing this post so above is a log of my actions taken.