Not able update publish post in WP theme Arras.1.5.1 with wordpress 3.2

I m not able to update my publish post created with WP theme Arras.1.5.1 with wordpress 3.2, It does not show any error, when i made some changes after publishing post, it shows in my admin panel, but does not shows in preview nor after click on update.

I had check all possible way to figure it out like clearing catch files, changing dates, etc. But to make changes (update) i have to delete same post and need to publish as new post with same name.

I know this is not an option for is problem. Can anyone help me out. plzzzzz