It's certainly complicated because of the heterogenity in Afghanistan with rival factions/tribes and the porous border between Afghanistan and Pakistan. The Pashtun people move back and forth across the border. The Taliban grew in the Afghan refugee communities in Pakistan, so they move back and forth across the border.
Pakistan's Chitral District: A Refuge for al-Qaeda's Top Leadership?
By Hassan Abbas
With respect to the last point, it is still an issue.
The US and some European Allies have Provincial Reconstruction Teams in Afghanistan.
I don't know how effective DynCorp is there, but I have my doubts.
Digressing a little further -
Four Years Later, Much Of U.S. Aid In Afghanistan Has Little Impact
By MARGARET COKER, ANNE USHER
Cox News Service
Monday, October 10, 2005