You are correct there is more than one issue here. FYI I also cleared the Appdata A3 Launcher folder. (first backed up the presets and other settings.) to force reacquisition/repair of these Launcher files. I also cleared the Steam Apps Common Redistributables folder to force reacquire (C:\Program Files (x86)\Steam\steamapps\common\Steamworks Shared\_CommonRedist). This seemed to also resolve a C++ lib problem in C:\Program Files (x86)\Steam\steamapps\common\Steamworks Shared\_CommonRedist\vcredist. Once I had cleared these files - I got Steam to revalidate the local file cache of Steamworks Common Redistributables - Steam then reacquired the above files.

I had the same problem when trying to import a preset from an html file I was sent. I have found the error - the output html file is formatted incorrectly - I edited the html and file now imports!