It means that they're going to participate in the government through following a negotiated process. In other words, if I can go back to the notion of civil war, my understanding--we can disagree on this--is that effectively what happened in 2001 is that international forces worked with the Northern Alliance, which represented parts of Afghanistan against the Taliban and other insurgents that represented other parts of Afghanistan. They still hold sway in large swaths or have regained sway in large swaths of Afghanistan. A national peace process will have to acknowledge that that sway exists and that it needs to be brought into line with a new more inclusive governance structure in Afghanistan. In other words, there will have to be a form of national reconciliation that includes Taliban insurgents in some way.
On November 17th, 2010. See this statement in context.