Can you move it over a little bit into a new area so that the screw can bite? You can then remove the knot from the rope and readjust. If not, what about one of those plastic anchor inserts. You can enlarge the hole to fit the plastic anchor, put some epoxy in the hole and push in the anchor. I've used all sorts of epoxy, but the easiest one is the syringe type that mixes the epoxy as you push.
2014 Georgetown 351DS
-TruCenter -Front/Rear CHF -Hellwig Links -Tiger Trak -Ran McNally GPS -ScanGauge -Truck Systems TPMS -5 Star Tune