OK, happy to have found the problem, thanks! Chasing ghosts is so frustrating ;-)
Deinstalling the 2005 runtimes was in a lot of Your advices and I tried before posting the problem, but there was one ugly thing: some of the 2005 c++ things wanted a source file file to deintsall, suggesting it in a TEMP Folder or looking for a non existing msi...wellknown problem, but i did not find a solution .... so it did not deinstall. Ho to deinstall those?
Maybe I should have taken those resistance aigainst deinstallition more serious? There are 5 (!)) versions of VC++ 2005 (x86 and x64) which resist deinstallation.
Moreover - are there English and German versions of that installed? At leats there is an option to chose among ENglish or German, when downloading the installers....
And the more I read about VC++2005, the more it looks like a total desaster from Microsoft. Why is Addon Manager relying/ depending on those bad files?
And by the way - thanks for not suggesting to reinstall WIn7 and /or FSX!
Greetings,
Michael
Edit: I managed to get rid of the old VC++2005 installs, which was hard work: only way functioning was this advice from a microsoft forum, it might help other simmers frustrated by the mess with VC++2005:
"To all fellow sufferers of this horrible C++ install plague, here is what worked for me:
Download uninstall
http://download.cnet.com/Revo-Uninstaller/3000-2096_4-10687648.htmlFind the C++2005 application in REVO and click uninstall but select the bubble with ADVANCED MODE scan
After it runs advanced mode scan, click checkbox for "select all" and DELETE all the entries which deletes all registry entries. It looks like pages of data being erased and it seemed scary but I knew I could download the file and install if I needed it (
http://www.microsoft.com/en-us/download/details.aspx?id=3387I could see in the control panel (add or remove programs) that the cursed C++2005 was finally gone.
I discovered the software I was using (Viacad PRO V8 Beta) was installing the C++ 2005 and getting some conflict with a previous C++2005 install. I'd tried the suggestions in 20 threads but could not uninstall the 2005 previously installed version (continous loop of asking for disk/location of vcredist.msi). Once REVO uninstalled it, I uninstalled the ViaCad pro & re-installed it. It worked fine.
I checked the control panel (add or remove programs) and could see the C++2005 was now installed by the program and all worked well. It just was a matter of getting rid of the stubborn prior version (which would not leave via control panel, sxstrace, & 10 other methods).
If your newly installed program is not installing the C++2005 with its installation, then just download the right C++2005 version from microsoft link above."
From here:
https://social.msdn.microsoft.com/Forums/vstudio/en-US/54746791-4af9-4bf6-86f4-9565d3850730/manual-uninstall-of-visual-c-2005-redistributable-version-805072742?forum=vcgeneral