Hmm, weird that only your latest save file has this error. You can try loading it in some previous versions of LD+, since it might be an initialization issue. If it works, make a save to update it, then try a later version.
I got it to work, thanks for the help. It seems to have been a problem of my installed game files, which only affected the newest save file for some reason. Completely deleting and reinstalling the game in the newest version worked (Which I tried after a new install of an older version also worked.).