After I enter a new area, I get a notification that Dog has died and then everyone else proceeds to die. Was there something I missed?

As Father Elijah says "If one of you dies, you all die."

EDIT: I honestly have no idea why Dog is randomly dying, I didn't even know companions could died in normal mode(not HC mode).

Ok, I've just found out that it's in any new area I enter that triggers Dog to randomly die.

Edit: I've reloaded a further save and gotten past this point with no problems. Are there any other bugs like this within the DLC?

Well, yes and no. With Bethesda/Obsidian games, there are a fair amount of bugs. But there is no saying on whether or not you'll encounter them. For example, I played FO3 and the only bug I encountered was the Wild Bill Glitch (where he and the ingots spawn under the level) in the Pitt. I would look up the known bugs for your system on the Wiki and learn if there is any way to prevent them, know you're a victim to one, or how to solve one. Also, I would use several saves (I use 5) that you can travel to in the event that you are bugged, which may undo it as it did for you. :wink_smile:

the only time that happen is when i did the console command "killall" thinking that he'll just get back up like they do in normal mode...only intill i seen "God/dog died" "Dean died" Christen died" then my head goes pop...remember kids never do the killall comand because it wont kill the ghost people but it will kill you. other than that ive hardly never ran into any bugs just only one and that was the Quest: "I could make you care." thats about it.