Hey guys,
I'm having a serious problem with my file in Skyrim right now where the quest "Bound Until Death" will not begin when I speak to Astrid after completing "The Silence Has Been Broken". Can someone please inform me of WHY this is happening? Below is a full list of completed and active quests that I have, if it might shed any light on the cause of my predicament. Thanks again!

COMPLETED:
Unbound
Before the Storm
Take up Arms
Hired Muscle
Delayed Burial
Joining the Legion
Lights Out!
The Mind of Madness
The Man Who Cried Wolf
A Night to Remember
The Jagged Crown
The Golden Claw
Bleak Falls Barrow
Dragon Rising
Proving Honor
Rescue Mission
The Silver Hand
Retrieval
Striking the Heart
Blood's Honor
Purity of Revenge
Glory of the Dead
Message to Whiterun
Battle for Whiterun
Innocence Lost
With Friends Like These...
Sanctuary
Contract: Kill Narfi
Contract: Kill Ennodius Papius
Contract: Kill Beitild
The House of Horrors
Mourning Never Comes
Whispers In the Dark
A False Front
The Battle for Fort Dunstad
Compelling Tribute
The Battle for Fort Greenwall
Rescue From Fort Kastav
Reunification of Skyrim
The Battle for Fort Amol
Battle for Windhelm
Contract: Kill Lurbuk
Contract: Kill Hern
The Silence Has Been Broken

ACTIVE:
Forbidden Legend
The Forsworn Conspiracy
Rising at Dawn
The Wolf Queen Awakened
Missing In Action
In My Time of Need
The Way of the Voice
No Stone Unturned
A Chance Arrangement
The Blessings of Nature
Silenced Tongues