Re: Fatal Error when activating
@Squashroby & @Tyviris-
It appears that both of you are using WordPress single user version. BuddyPress must be used with WordPress Multi-User version (WPMU).
You can download it here: https://mu.wordpress.org/download/
Start over from scratch. First, delete all the files (except any custom themes you may have created or downloaded). Create a new MySQL database. Them go though the install process again: