BuddyPress.org

@1stAngel; Groupblogs is not presently compatible with wpmu 2.9.1.1 (for many). At the very least you’ll need to add the code mentioned in the middle of the linked topic below. That may, or may not help as results seem to vary. For me (with bp1.1.3) new group members are not automatically becoming blog members unless I promote them to Mods or Admins. Hopefully once bp 1.2 is stable the plugin can be updated to work well with 1.2 and wpmu 2.9.1.+:

https://buddypress.org/forums/topic/bp-groupblog-error-call-to-undefined-function