Warning in Buddypress on one sub-domain

I love this plugin! It works perfectly on 7 of my 8 sub-domains. On my one sub-domain however I am getting warnings of

Warning: in_array() expects parameter 2 to be array, null given in /wp-content/plugins/buddypress/bp-core/bp-core-filters.php on line 199

I tried reinstalling BuddyPress but it didn’t help. I have had to resort to going back to my original copy of my primary menu.

Can you tell me please how I might troubleshoot this. I’m a wee bit familiar with making changes to phpMyAdmin if necessary.

Thanks!