Visual Composer not displaying content in website

Hello,

I am using a WordPress Multisite setup. I network-activated the theme and am able to use it without issue for a sub-directoiry site. However, whenever I use Visual Composer to add content to a page, that content is not displayed properly on a web browser.

Instead of the text content, I am receiving this error:

Fatal error: Call to undefined function vc_column_offset_class_merge() in /home/sitename/public_html/wp-content/themes/HighendWP/vc_templates/vc_column.php on line 16

Can you help?

Thanks,
Mike