Snake Fairy,
I've not had this problem myself, I'm not a technical person, and I'm not exactly sure what might have caused this problem ... however ...
When installing the game - did you install to the default directory?;
C:\Program Files\Black Isle\BGII - SoA\
If not - the patch (
Shadows of Amn patch and
Throne of Bhaal patch) may struggle to find the files.
By the way - once you've installed the correct official patch, it's highly recommended that you also install the appropriate
Baldurdash fixpack that corrects a string of minor bugs not addressed in the official patches.
I assume that you've not installed any other mods on top of your (unpatched) game.
My inclination would be to copy your last save to another folder on your hard drive, and uninstall-reinstall again, and have another go at installing the official patch (and Baldurdash). Return the saved game back into the appropriate folder, and reload. The game that you're playing may fix itself automatically with the reinstallation, but you
may need to brace yourself for the possibility of starting a brand new game.