Try installing Fiddler Everywhere with an account that has administrative rights (this is a mandatory requirement), Also try running the failed command manually in your command prompt.
cmd.exe /c ver
and let us know if you see the expected output, which should be something like
Microsoft Windows [Version 10.0.17763.1457]
Samleblond007
Hello,
I tried to install Fidller Everywhere on my windows 8.1, but i have always the same error as you can see on the below picture.
Please how can i solve this error?
Best regards.