The error is telling me that the map has a nil event, which should never happen in RMXP. My guess is that whatever script you are using is not changing the IDs of the events it adds, so the second time you add event with ID 5, it actually gets put as ID 12 or something similar, which causes a conflict in RMXP's default scripts. This problem doesn't seem to have anything to do with Blizz-ABS.