Yeah... I didn't really check the code or test extensively since I was not going to report this yet. However after some minor testing it seems the error message comes from WPI detecting my system uses Swedish and recognizes it using ISO 639-1 (sv). So adding a file with those values will make the error go away (as it then knows there is a language file available). However when selecting and loading a language ISO 3166-1 (se) is used. At least that is how it seems to work, but I'm sure mritter could tell us if I got it wrong. I do believe that this is the likely issue since just duplicating the same file using both ISO standards removes the error as well as makes the translation be selectable as normal. Therefore I don't believe there is a case of missing lines or something similar. btw mritter: have you tried any graphical diff utilities for comparing files like WinMerge for Windows or Meld for linux? I would highly recommend both of them. EDIT: Man, I got confused there for a while 639-2 is the 3 letter language code, 3166-1 is the country code (se)