Hello, I'm the programmer of Nusakana. Actually, this is not the first instance of this problem to be reported, but this error is very related to folders and things. And as you may understand, we have close to no experience regarding Spanish PCs. We might be able to issue a workaround within the game to make the game work for Spanish PCs.
Firstly, may you screenshot how folder links is written within your PC? Something in vein of this. Any folder works.
Thank you for your cooperation and sorry for the inconvenience...