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.