I'm 79 on my team (pally, disc priest, 3x frost mage) and am having troubles with this boss .... can't outheal his dps even with full out heal-spam.

Here's the link to a better-than-average attempt: http://www.youtube.com/watch?v=iCRIi1LZdnU&fmt=22. He wipes me almost instantly at 1:12 when i'm at 80% health even when a flash heal hits me.

What am I doing wrong?