Alliance Succubus Quest

I am on the final phase of my succubus quest. I have the heartwood and have the chain step to summon and defeat the succubus. When I use the heartwood on the summoning circle in the basement of the Stormwind Tavern, the summon graphic happens, the ground shakes...and low and behold...nothing is summoned.

This problem apparently occurred after the last database modification.

The quest is called "The Binding".

The quest objective is to slay the summoned succubus, and since she is not summoned, she cannot be slain.

Please look into this. Thank You.