Your save file will be saved somewhere on your machine. When you run the game and click Load, just browse to the location of the save file.
Viewing post in How do I carry over saves to different versions of the game?
Strange. It loads up no problem for me.
Just so I'm clear, these are the normal loading steps.
* Bring up the pause menu.
* click LOAD
* browse to the file OK.txt
* click on it
* click OK
* On the Load Game? panel click Yes
* Game loads.
How far do you get in the process?
Also I you might want to put the file in a different location (like the desktop) and browse to it there. See if it can load it like that.