It looks like your rollers have moved. I am working on my slide now. Same problem except my slide has black burlap wrap over plywood. The mounting screws for rollers pulled out of the wall ( 4 screws each roller). Wood that rollers are mounted on looks like plywood, maybe 2 pieces of 3/4 glued together. My T.T. is a 2008 FR surveyor. Edited to include.
The bottom header has some soft spots where all the screws were driven to hold the rollers. Think I am going to install some 1 1/2" plywood that I have epoxied together and use epoxy and screws to attach the wood. This will set the rollers back 1 1/2" . Will post how it goes.