WSE and GOG.

Is it possible to use WSE mods with the GOG version of Warband? When I try, it asks me to activate the game, but the key in my GOG account is denied. I have been in touch with GOG support, but they can't say whether the key should work for anything other than MP on the GOG version ( which it does).

go here  https://forums.taleworlds.com/index.php/topic,324890.0.html

read OP description (how to use the vanilla .exe)

if in doubt you can ask in that thread

in case you dont know: you should be able to download the game from TW website and use the same serial key from your store (Steam or GOG).