I think what Mr. Robertson said is correct. It is final and binding, and every international agreement is an agreement between two sovereign nations. You cannot force a country to listen if it doesn't want to. This dispute settlement is so good because it is almost like a commercial arbitration setting. An arbitrator gives an award that is final and binding, but at the end of the day, between two sovereign nations, you still need to have the opportunity to consult if there are problems with any aspect of the agreement.
On October 3rd, 2006. See this statement in context.