Namur: Yep, i got the same thing but luckily it was easy to fix

-i created a folder on C:\ called SAVES
-i edited the sword1.ini file and pointed the save path to the folder i created, meaning i changed the savepath to

C:\SAVES

It's saving fine now. I'm guessing the problem relates to the path to the game folder being too long when it comes to creating a save file.