are you playing on a new save file? Or are you using one that is saved just before the new chapter? If you are, I put out a statement on all of my releases that there will be errors if you play the newest chapter with an old save file. This is due to changes in the script from previous chapters, meaning you will need to play through those first. If you have a save file around chapter 4 I would say that is the safest place you can use an old save file.