Shows 404 after I creating story/page

Hello Dear Readers,

I've been facing some really weird problem since I installed drupal again. It is a new drupal installation and there shouldnt have been any problems as such but let me describe it.

When ever I am Creating a page or a story, it shows 404 in few cases.. like any word starting with BO.. it shows 404,

then there were few other situations when I had to remove the whole para in order for the node to be created

I looked over drupal forums and google aswell for such problem but did not find any solution, is this because of the new version 5.5 patch?

www.frankzzsword.com is the site where I am facing this problem