Setting up sitewide forums can be a bit tricky. After you install and activate bbPress, you’ll need to add the bbPress shortcode for your forums index to that page:
Check your bbPress settings page in the dashboard to see if you’ve got a page/slug conflict with BuddyPress. If you have any trouble, you may want to try unticking the Discussion Forum box in the Components setup page. I’ve found that this helps users who are getting the error: “The forums component has not been set up yet.” I’m sure this process will be smoother in the future, but for now that hint may come in handy.
I was running into the same issue as you, and this solved it.
Good luck!
