Watching the fight, it's possible your problem is healing. General Bjarngrim is a fight that doesn't permit you to have your tank's health at anything less than maximum at all times, yet for stretches of the fight it seemed your tank was operating at half. In the same period, your priest appeared(?) to be idle. Your tank's health seems to be at a point that can survive the burst, so you might need to do something to increase healer throughput to make certain your tank's health is topped off -- either adjusting talents or spec; moving healing off into a spammable and high mana macro specic to this fight; or giving healing a bit more attention.

I'm a big fan of keeping healing as simple as possible, doing nothing more than spamming gheals.