Hello Bernhard! Welcome to the new forum.
Please make sure that you have the latest Visual C++ from Microsoft installed. See FAQ - FMS Error "api-ms-win-ctr-runtime-l1-1-0.dll" or "(0xc000007b)" for links.
If the issue persists, I need logs from the application to assist you further. You can find them at C:\ProgramData\Navigraph\FMSClient\logs and then attach them to your next post!
Regards,
Malte