What version of the game are you running (Impulse will tell you, or look into the bottom right corner in the games main menu).
Now open the .galaxy file with a text editor and check the "versionNumber" at the very top. it has to be 2 if you play 1.1 or later, 1 if you play 1.05 or earlier. Just edit it and save the file (check if the text editor appends .txt after the .galaxy and correct that if needed).
