White piece of plastic came off slide out - need help

Most Nylon Glide strips have multiple holes because just having 2 screws on each end will not hold it in place. IF you have the multiple holes, make sure you install a screw in each hole. If you do NOT have multiple holes, I would drill and countersink a hole every 12 inches to install additional screws. IF you have multiple holes and they only used the 2 end screws, that is why it failed. Doug

It goes under the slide at the edge of the wall and the entire s/o "slides" over it as it travels in and out. This type doesn't usually have rollers, just that slippery white guide.
Without it you will tear up the bottom of the slide. It was probably broken the same way mine was, by stepping on the unsupported floor of the slide while it was in.
The slide will have to be lifted or even removed to screw the piece back in. Mine wasn't that bad, just cracked, so I installed rollers to help support the slide. A much better system.
I'd post a pic but Photobucket lost all those images.