Well....OK. Here's what happened. I still got the error message and AOP and AOE (on Hyperlobby) are running a different version fo the sim, with 4.12.2m in parenthesis. At startup, my game shows 4.12.2m HSFX7.03 too. So I will assume that my roll-back (by installing 4.12.2m over 4.13) was a failure. I'll have to delete the folder and try again, unless there is some useful tip I've yet to discover..
Flyby out