I have installed latest version of wordpress in root folder of the domain and it works fine with default theme. Whenever I change it to installed theme it gives this error message:
Fatal error: Call to undefined function get_header() in /home/shane/public_html/index.php
Problem Solution: Check with your uploaded theme and it must be inside the wp-contents/themes folder in order to work with the theme. It seems that in this case theme is uploaded in the root folder. Please move this theme inside the theme directory of wordpress. Once you move theme to wordpress theme directory it will resolve the case.