it is not in gcf format
but in ncf
means: you have some small ncf files which contaion informations about the files which should be present at \steamapps\common\<game name>
so it isn't enough to just have the ncf files
you also need the files which have to be in \common\earth 2160
after that you need to replace the exe and apply a reg fix
then, after launching, still the process of activation
don't worry, i've upped the fixed exe, the reg-fix and 2 keygens for you
here