No matter where I am or where I fire it from, Auriel's Bow doesn't work for me.

When the sun is out, it doesn't do anything.
In Solitude and in Dawnstar, the sun doesn't ever seem to come out, no matter what the time of day or even if I use Clear Skies shout.

Clearly this DLC was rushed. When I pick up the Auriel Bow, the game doesn't give me the last quest. (Kindred Judgment) . So i got the bow, but not the quest to confront Harkon. This is depressing coming here seeing everyone reporting sooo many dawnguard glitches...

I was having the same problem until I tried re-equipping the arrows, the sun wasn't going dark, just shooting into the sun with nothing happening until I took off the arrows and selected them again, next shot worked as it should.

Yes it is. Also, I am sorry to hear you ran into a game breaking bug. I've run into a lot of bugs in this game, but thus far nothing that is game breaking (knocks on wood). Still, they are all annoying as heck, so I feel for you.

At this point, I am taking solace in the fact that they will probably give everything a major rework, and hopefully they will add in some nice things for all the fans (cough... marrying Serana... cough).

Perhaps you should just try a different location where you can see the sun. You were using the Bloodcursed arrows with the bow? If so just try Kudreon's suggestion about re-equipping the arrows.