For a
DVC rental with a broker to work, a number of things have to happen.
A owner has to want to rent their points.
They have to contact your broker to rent those points.
The points have got to match your request (within reason - few expect an exact match, but if I want to rent a week in a two bedroom worth of points, I might not mess with several studio reservations and wait for the two bedroom - and in fact I did).
That person has to respond to the reservation request - with a busy day, or being out of town, they might pass anyway. (I also did this, there were a few days reservations came through that I was too busy to deal with them and passed).
Then the room needs to be available.
Its a little easier without the broker, if you can find an owner here on the rent trade boards or through another connection, but some resorts have a much higher demand for rental than they have owners willing to rent their points. VGF is one of them - and honestly, it isn't really economically desirable for those owners to rent anyway - their buy in costs were pretty high, they may still have loans.
That's why people are saying have a backup plan.