BlackArchon
Warlord
...
There is no version checking on patch A either. It simply looks for FfH2 0.41 to be installed on your computer. The error message you received is the result of an invalid location being provided to the installer. When you launch the Patch A Installer you are given the opportunity to select the location of Fall From Heaven 2. By default the location provided should be your "Civ IV\Beyond the Sword\Mods" folder, which should be correct. If some other location were to appear, or if the user mistakenly changes the path to "Civ IV\Beyond the Sword\Mods\Fall From Heaven 2" then the patch will be unable to install correctly.
I'm sorry, but the patch didn't let me choose a folder. But I extracted the content of FfH2041a.exe with the help of 7-Zip and overwrite the old files. Seems to work.