All okay again!
In a first step I have installed the .dll from "C++Runtime" again, as you can read in the WOFF-message above, at first the older one "vcredist_x86_2008_SP1_ATL_Fix" (12.08.13), then "vcredist_x86_2010_SP1" (22.09.2024). I have had no success. With the third mission I have had the same problem again. But I can't remember, If I have started WOFF directly after installation or If I have restarted the PC at first.
Then I have installed Patch 1.06, have restarted the PC and all was okay with WOFF again.
That's nice of course, but I have no explanation, what has happened. Maybe one of these points:
+ The new dll-installation (I only forgot to restart the PC)
+ The patch 1.06: It has repaired airfield Roucourt, Flandern, in the air activity-circle of my airfield Balatre field.
+ I can remember, that I have leaved WOFF during a mission via a wrong button accidently.
+ 2 or 3 times I went back to main menu during the "ground crew preparing flight."
Only 3 mods I have sometimes in use. I list them only for compliteness: The OTT-ßetaTuner-mod by @VonS, the FPS-impovement by @PR, and the OTT-stock-populated-airfield-mod by @PR.
P.S.: For safety I will make a copy off OTT, Vers. 1.06, on my drive D, because you can't install a WOFF-patch a second time.
Greetings