Ah, my bad. I understood the question wrong.
:
But for you're question:
The path it tries to install the patches is the original path for the game, if you've bought only Overture in separate box.
And I guess it's the same thing with Black Plague and the path, yes?
I have that path as original in my installation of Overture.
Just install the patches where ever you like and then run them. It doesn't matter where you've installed them. (If you like, you can delete them after you've installed and runned them.)
But before you run them, make sure you install the game first that the patch is made for.
:
They're useful.
For example, without patch, you cannot finish Black Plague at all.
Known bug with all the Black Plague games around the world... (Don't know about the downloadable version though.)
And in case you're using ATI's HD graphics card drivers, you'll have to install patch for Overture. It fixes the graphic bugs.
But are the patches the latest?
For Overture it's version 1.0.3.
For Black Plague, I can't remember, but if Overture is the latest, then I guess Black Plague is as well.