Posts Won’t Load

I did ask earlier but never heard from anyone. Maybe I’ll be luckier this time. My site has 240 posts (called Chapters on my site). Until recently, it had 241. That post was working and could be viewed by any viewer. But Chapter 241 suddenly disappeared and can’t be reloaded. I discovered this when I tried to add Chapter 242. All seemed normal as I did this. I clicked on “Publish” and got the usual results. I could click on ‘Edit,’ make a change and then click on ‘Update.’ But the post would never load. And then later, Chapter 241 disappeared. In Settings-Reading, the total number is 350. I contacted SuperbThemes as it designed my theme, LifestylePress, and was told to go to the WordPress Support page. And here I am. I hope someone can tell me why I can’t add another post – and why one was deleted after being there for awhile. Thanks.

The page I need help with: [log in to see the link]