Did you double-check to see if the installation put everything in the right place? You say your install path was D:\GameApps\Steam\SteamApps\common\Star Wars Empire at War\corruption\Mods\Imperial_Civil_War - have you checked to make sure there's a Data folder inside, rather than a doubled up pair of Imperial Civil War folders like was happening in another thread?
Also, when launching through Steam, are you selecting Empire at War or Forces of Corruption to play? Because it should be the latter.
Yeah I checked and it goes straight into Data from the civil war folder. I've been launching Forces of corruption as well. I honestly don't know where it's gone wrong