ok... maybe I've found a solution
In italian version of BG SoA the installation makes a dir named "data" under main dir "BG2 - SoA" and other 4 dirs named "data" too under the cd dir "CD2", "CD3", "CD4" and "CD5" that contain also a dir named "movies".
The cd paths are in "baldur.ini" or in "config.ini" (I don't remember now).
I've changed those paths and redirect all them under the main dir "BG2 - SoA" and then moved all the bif files contained in the four "data" folders to the main "data" folder and all the movie bif files contained in the four "movies" folders under a unique new "movies" folder under tha main dir.
In this way the game start correctly... I hope that it will continues in the same way!
I hope I helped you!