Grrrrrr Mine broke too. To replace the broken runner, I have to remove the whole lower rail which is glued, siliconed and screwed into place with snap fittings on the vertical end rails. Then the plastic "cabinet" or box that holds the rolled up screen broke - the bottom snap snapped off so the box hangs open.... The whole thing is very inadequate. I am looking at the Schub RV folding screen as a replacement- there are some positive reports about it.
"I carry what I can, and leave the rest behind" Epicurus
"All that is mine, I carry with me." Cicero