Player item/gib/hwm .mdl files not appearing in the "Select .MDL file" menu.

Like the title says, this is an issue I have been trying to sort out for the past 2 hours with little to no success. It used to work, then I installed Source SDK 2006 and then they stopped showing up. I have done as much as I feel as I can at this point so I am gonna request help from you fine chaps.