I downloaded the the main game and the Friend's Pass. It gives me an error stating - Missing Executable. HELP pls.

I redeemed the game from a past Humble Choice bundle and I see this Friend's Pass in my library now. What is it? Why do I have it? How do I use it to play with a friend?

Я купил игру, отправил другу код на Friend pass, вроде всё отлично, но при запуске Friend pass у меня и друга вылетает ошибка "не найден исполняемый файл" помогите решить проблему, охото вместе поиграть :)...

Hi everyone. I am trying to accept invite from my friend who give me Friend's pass and nothing happens. If the game not opened - accepting the invitation takes me to main game's shop page. I am running Russian version of the game.

My games doesnt give me the friendpass key