I'm confused by this message within the Installer:
The "Dark Side of the Swordcoast" mod uses some sound files from "Icewind
Dale". If you have this game installed the Installpack can copy them into
your BGII game. The folder "Icewind Dale" is not in the same directory.
Type here the path for your "Icewind Dale" directory and press ENTER.
There is nothing in the DSoSC readme which indicates Icewind Dale as a prereq, and the Installer won't let you proceed without an entry.