Download
This File straight into your main Supremacy folder, and it will ask you whether to overwrite the existing version of the file. Say yes.
Next, click on Start => Run, and type "%temp%/UAB" (Without the quote marks) into the box that appears and press enter. A folder called UAB will then open. If there are any files or folders inside the UAB folder, delete them
all, then load the game and cross your fingers. This fix also works for problems with the updater.