How Lulu the Monk's team exploited HoH : GW Submissions

Balthazar's Aura
Enchantment Spell
For 10 seconds, foes adjacent to target ally take 10-22 holy damage each second.
25 Energy, 1 sec cast, 15 sec recast

Load up on items that improve Smiting Skills recharge
Everyone use Balthazar's Aura on designated target
Balthazar's Aura stacks so w/ 8 ppl casting Balthazar's Aura, you do 8x22 = 176 damage <b>PER SECOND<b>. If you have people w/ Arcane Echo or Echo, then you can put more.
You -should- only 1 of each type of enchantment spell on you, but ANET has not fixed this glitch yet.

latest patch notes:
Fixed issue with Balthazar's Aura skill, so that when multiple copies of the buff are cast on the same ally, only the most powerful is active.

As said in the post above this bug was fixed with the patch released just(about an hour) after you posted. Sorry, better luck next time.