I was faced with a similar situation for another property and called Cust. Serv.

I found out that in many cases for resorts, the base amount of points does not access the lowest room type available on a specific date at a property - so even the lowest award available might need $$ or Upgrade cert. to book.

One way to check is to input a date a few months further out and see what's available. I was looking at a "Deluxe" room which needed $55 per night or 5,000 points, because the "Quality" room category was booked. If your rate includes PAID or POINT upgrade, that's what you will need.

http://marriott.com/rewards/usepoints/hotelrmup.mi#tips

Hope this helps.