Fatal Error message on Activation

Hello,

Please I’m in need of an urgent help in installing and using this Gazette theme on my site. On installation, it gave me this message:

“Image Size:
Fatal error: Call to undefined function genesis_get_additional_image_sizes() in /home/content/25/11296325/html/wp-content/plugins/genesis-tabs/plugin.php on line 258”

That prevented me from going further in customizing the theme and using it. How can I resolve this?

Thanks.