Strange problem?!

I start with apologizing if I’m posting this question in the wrong place… I hope you bear with me and that some of you might have a solution to my strange problem.

I have built a WP site for a friend. The site is based on Starkers theme and has now been up and running for a couple of months. The site has a number of pages and a news page with blog posts. Yesterday it seemed something strange happened (as my friend was making a new post) and the news page doesn’t show what it ought to show. There are no posts visible and instead of the blog sidebar, the sidebar show sub-menus from the site’s other pages. All other pages on the site are working perfectly fine.

The first thing I did was to activate the WP default theme and the problem occurs also there. I then went back and clicked preview at the Starkers theme and in the preview mode I saw the site and the new blog post running as it should. But when activating it the blog posts still don’t show.

http://www.coreimagesthlm.se/?page_id=25

Does anybody have a clue what might have caused this?

Camilla