Fatal error: Call to a member function set_404() on a non-object in /home/hailtr

Fatal error: Call to a member function set_404() on a non-object in /home/hailtrac/public_html/wp-content/plugins/buddypress/bp-core/bp-core-functions.php on line 1459

pretty sure i’m getting this on my child sites as a result of mixing bp-multisite plugin while using the enable multisite plugin, if that’s the case is there any way back out of that mess or best to just start again? ex. http://hail-track.com/demo/