No big deal for me, but you might want to know that your installer didn't even create the planetfall v8 folder for me.
-I downloaded the main file and the patch from the links at the top of
http://forums.civfanatics.com/showthread.php?t=253775
-I accidentally ran the patch installer first, but realized this as it was finishing
-I then ran the main installer, followed by running the patch installer. The directory they suggested (and I accepted) was in both cases
C:\Program Files\2K Games\Firaxis Games\Sid Meier's Civilization 4 Gold\Beyond the Sword\Mods
-I started up the game, and was surprised when I could not launch the mod; on investigating I realized that even searching my entire civ4 folder for "planetfall" returned no results, much less finding a folder "C:\Program Files\2K Games\Firaxis Games\Sid Meier's Civilization 4 Gold\Beyond the Sword\Mods\Planetfall v8\"
-I went ahead and created that folder myself, then tried the installer again; no dice.
-I used 7zip to extract the files myself into the path above, then extract the patch files (overwriting when it prompted). I then was able to load the mod and it seems to work fine.
-FfH2 also uses the NullSoft Install System v2.38, and FfH2 correctly installed for me.
As I said, it isn't really a problem for me but I thought I'd let you know. For your information, I'm running Civ4 BtS 3.17 on XP.
Amazing work by the way; I'm certainly impressed.