I am using admired theme, and i am facing the same problem. recentrly my website look was changed to disturbed. then i changed my theme to an other theme, and then again installed admired theme and every thing is working good same like before but now when I click on a post link the main sidebar disappears. If I click on an archive or category the blog posts display and the main sidebar.
you may see the problem at my website http://www.bigfashionstyle.com