Why theme has positioning issues after being installed?

Hi there,
So i am again trying a new theme i found at:
http://www.themesjunction.com/theme/fashion_magazine_7_wordpress_template-2151.html

After i installed it there seems to be positining issues on my wp of the theme:
The top section of “This is the Top Post” which should be below the row of the 3 images actually starts right below the header image (of the sitting lady) and then below the 3 images there is a grey break and then the Top Post section continues.

So the theme before instal on the preview looks very nice, but after install looks very messy.
Any idea how to solve this?
Thank you.