Installation Autofocus Pro

Hi,

I was using autofocus for my website, but yesterday I wanted to install the autofocus pro version. I can not see my website anymore and I get below error message . Does anybody know how to solve this?

Thanks

‘Fatal error: Call to undefined function has_post_thumbnail() in/home/content/i/s/e/XXXXX/html/wp-content/themes/autofocuspro/thematic-functions.php on line 44’