theme line 21 error

Hello,

I get front page error with your theme Blogs MU

Fatal error: Call to undefined function groups_get_total_group_count() in /home/…/wp-content/themes/blogs-mu/lib/templates/wp-template/sections.php on line 21

Plugins used:

Akismet

BuddyPress

Pricing table

WPMU DEV Dashboard

What does this mean?

Thank you for your reply.