posts disappearing! please help

I’m trying to set up a multi-author p2 themed blog at http://www.athensfeed.com.

When I create a post from the front page, it loads in the recent updates but disappears when I refresh the page or visit another page and go back to the home page.

When I create a post from the back end, it never shows up on the front page.

All the posts are available, however, when I look at the categories they are posted to (sidebar links).

Any idea why my posts vanish from the homepage?