Hi Willa, To work well, the top and bottom tracks need to be parallel and solid. I do have a wooden base under the steel GH base, and that might provide some stiffness to the bottom track. One idea is adding an extra brace to the frame right over the top of the doors, to stiffen up the top track. That seems to help the doors operate more smoothly too. We just added a piece of oak we had, but others folks have used a piece of EMT or aluminum angle in the same spot. The idea is to help prevent the top track from sagging at all if possible. (click to enlarge) Also, this is a good thing to check...there's a small illustration at the bottom of page 15 of the manual, labelled Side View. (Shown below.) This shows you that the small black plastic clip Part 51 has to be guided onto the bottom door track so the small vertical part of the aluminum track is actually threaded up into the vertical gap in the center of black plastic part 51. If you do it right, the bottom leg of the black plastic "L shape" goes down the front and under the L-shaped aluminum door track, as the illustration shows. If you don't install it just like the manual shows, it's actually possible to install the doors so that the black plastic part 51 is just sitting on top of the door track, sliding along in the small valley there. Although your doors can function (sort of) this way, they can also fall off, since they're not truly captured at the bottom in the manner the kit intends. My doors can't even be pulled off the track, top or bottom. I've honestly never seen anyone comment that the wheels can be pulled off the door itself, and there really shouldn't be that kind of pressure on the door to cause that at all...it makes me think something else is wrong with your door tracks (problem with your bottom track rising up?) or, with the black clip not being installed quite right, as in the illustration above. I'm kind of scratching my head over what would possibly cause that. :-( This part of my blog talks more about the doors, in case there's anything helpful here to you: Assembling the roof, windows, and doors

"Could the installation of the tile have caused the frame to close in?" Yes, especially if the door frames did not get nailed off to the floor adequately. If you used the prefab pocket door frames it is actually very likely they did not get nailed off to the floor. It takes very little pressure to bend a long piece of 1x lumber the fraction of an inch required to cause rubbing on the door. If the wall is drywall I would cut a hole to see what is rubbing.

I've heard good ol' BONDO does wonders in such cases, and of course it will NEVER rot or succumb to water. You said it's just for a shed, so maybe it doesn't matter if the result is not perfectly matched with the adjacent good wood...? I have no hands-on experience with the Bondo-on-wood game, but I am about to get some on the lower few inches of a doorframe that has rotted. Need to stop that process before it spreads up to the lower hinge. I have used Bondo's cousin, Marine-Tex, to repair fiberglass boats, but that was a while ago... ;')

Post the pictures again.