Guys - this is just happening because your board is warped and sagging. Probably nothing has come loose, just the carboard underneath the fabric is starting to bend under its own weight. I fixed it by removing the board and epoxying a thin piece of aluminum bar stock (available at Lowe's, etc) to the underside of it. Thin enough that I can bend it slightly to get the board to match the curve of the roof, but strong enough that it will never sag again.
http://dmctalk.org/attachment.php?at...5&d=1364141335
Unless when you remove the board you find what Dennis did, that your clip isn't installed properly :)