Supreme Ruler 2020 default.unit file error

Hi!
On my computer I have installed Windows Vista and I upgrade it for games. Currently I am playing Supreme Ruler 2020. I have installed upgrade that I got from one of the forums. I can't remember what version of the update was. But all I know is that I got an error message when I want to start a game.
Can someone help me with this?
My best
Dexter
File Open Error
Cannot open file: D:Program FilesSupreme Ruler 2020GoldMapsDataDEFAULT.UNIT.
Could not find a part of the path ‘D:Program FilesSupreme Ruler 2020 GoldMapsDataDEFAULT.UNIT.
