ok forget about all of them. (no offense)
Close steam.
go to
http://mirror.player.to/sourceforts/sourceforts193.exe and download the installer version.
Once it is done downloading, double click the icon.
Follow the instructions. The folder it will install to will be the correct one by default.
Once it is done installing, start up steam again. Go to your games tab and start sourceforts. =)