I am having this same problem except that I have BG1 EE and SoD, my steam install is on a different letter drive-
G:\Games\Steam Games\steamapps\common\Baldur's Gate Enhanced Edition
Baldur's gate 2 EE is installed here-
G:\Games\Steam Games\steamapps\common\Baldur's Gate II Enhanced Edition
It's saying invalid directory on the BG1 SoD part.