Kara

Well before we attempt first boss should have the following kinda classes

2 x tanks - MT / OT
2 x Priest - Holy (with a bit of +Hit gear, to shakkle undead mobs)
1 x Mage - Buff, food, water, dps
1 x Lock - Dps +imp buff(stam), health stones
2 x Healer - Treeform druid, shaman, pala
2 x Other Dps (rogue / hunter)

Something similar to that to make it go smooth