5
Click on this link
http://caribbeanancestry.com/forums/modules/newbb/rss.php?c=5 <<< this is the type link feedburner wants
It's the RSS feed of everything in your "Caribbean Genealogy Category" in Newbb (CBB)
Click the following link and you will see a little orange "RSS" feed icon (it's only small)
http://caribbeanancestry.com/forums/modules/newbb/images/rss-a.png
When you see that orange icon or similar it will have a mostly unique link to a RSS feed, Newbb is full of different RSS feeds, nearly everything in Newbb (CBB) has a feed, Categories, forums, global.
If you click on the orange icon you could just copy the link from the page that appears, that may be the easiest way to explain it.
;o)