I'd maybe try adding the folders for all the other culture interface files,including the other tga's that aren't changed and for the other cultures. Adding them in shouldn't hurt (I think it would be same as set up I had then as we'd changed other things in the files already). That might be safer than having it look partly in one folder and partly in original.


Other than that no-idea now, it seems very strange that it seems to work once then break as those files shouldn't be getting overwritten or changed in any way by game!