The walkway that runs from Disney's Polynesian Resort and the Transportation and Ticket Center (the Magic Kingdom Parking Lot) has been temporarily closed as part of the resort's construction work.
Directions are in place, taking guests along an alternative route to the Polynesian Resort. The pathway will re-open once the construction work has been completed. It's likely that the actual foot path route will be slightly modified to accommodate the new Disney Vacation Club wing of the Polynesian Resort.