I've been playing since MTW1 and have been modding since Empire FYI. I've never seen this before.
Just prior to the latest patch I was 150 turns into a AoC campaign running only the 3 Radious mods for AoC. I started getting this error when the game would crash the second I clicked play.
I deselected the mods, still the error.
I deleted the mods from data folder, still.
I deleted the data folder, reacquired, tried to start with no mods subscribed or in data folder, still.
I deleted the entire Attila directory and the appcache folder, reinstalled, still.
Something is wrong big time.