I think Entertainmentwise is among the group of tabloid sources that Contact Music, New Kerala and others belong to. Once one of them reports some gossip, the same gossip usually makes the rounds of all of them, and then sometimes a few months later they recycle them again just for good measure. None of these are worth worrying about
In this case, I think they have confused Christian and Johnny with their Public Enemies characters, Melvin Purvis and John Dillinger
Totally silly, especially with all the parallel reports in the news right now about how little Johnny cares that The Rum Diary isn't doing great at the box office. From what I could see, Christian and Johnny had only positive things to say about each other during Public Enemies; Johnny almost never says anything bad about anyone anyway. I do seem to recall some of the other actors or crew members remarking that since Christian is more of a method actor that he would sometimes be "in character" and didn't really interact that much with the rest of the cast, whereas Johnny would chat and joke more between takes, but even that isn't really a diss of Christian so much as it's just an observation that they have different approaches.
To be honest, I would expect The Dark Knight Rises to make at least 2-3 times more than Dark Shadows. It is in an established franchise that has done amazingly well and shows no sign of slowing down at the box office. It's really not fair to make a direct comparison between the two, anyway.