I downloaded this game through Galaxy and GOG's official language pack for Spanish through GOG downloader. When I run the file <language_pack_blade_of_darkness_5_spanish.exe>, a window pops up with the following message:
(!) This pack does not support your version of the game
please download a new installer
So, what should I do?
I downloaded both of them through Galaxy and worked fine. If you are downloading the language pack trough the Downloader because you can't find it on Galaxy (and I suppose the reason is among that field, since you are already using Galaxy :P), just click the language field ([shitty] picture attached), and it shall enable you to download the desired language pack.
The download works, but when I execute the file, it won't work (as I stated in the original post). And, if I go to CONFIGURE and change language to Spanish, it will ask me to put the CD in (which I obviously haven't). I sent a report to GOG Galaxy (Mantis) about this, so hopefully they solve it soon.