To install this on the Steam BTS version of the game, go to the steam folder ".../steams/steamapps/common/Sid Meier's Civilization IV Beyond the Sword/Beyond the sword/". In there create a copy of any file and rename it to civilization4.exe
now launch the Blue marble installer and lead him to this folder and click on the "civilization4.exe" and it will install normally.
Civ4 Blue Marble v4.50 Gold 2016-10-05
Civ4 Blue Marble v4.50 Gold
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