Fatal error on Global News WordPress Template

Hi there. I’m encountering a problem here.

I installed WordPress at https://ismamesir.com/v2/ and installed Global News template form Instanthhift.com. Everything works fine except when I clicked on the post link which is: https://ismamesir.com/v2/2010/12/jiwa-yang-terhalang-dari-taubat/ the following error message appears:

Fatal error: Call to undefined function related_posts() in /home/ismamesi/public_html/v2/wp-content/themes/globalnews/sidebar.php on line 52

and the post didn’t appear at all.

Any suggestions?

Thanks in advance.