you may have to start over from a previous savegame though as the npc dying issue seems to be attached to the savegames themselves when the first trainer was used. Chris had the same issues with my savegame and for me, reverting back to an older (pre-trainer) savegame worked perfectly.
I saved the game after getting the medicine from the priest,then started the game up with the new trainer and got my first mission after that and nobody died so it looks good for now,Thanks.