BuddyPress.org

I had this problem too, I found that it was a conflict with some of my plugins.

First, take out any plugins in /mu-plugins and try to activate the email again.

I found that wp-super-cache was causing some conflict in my blog, I took it out and it works perfectly now.

Then, if your activation works, place the buddypress plugins back in /mu-plugins and try to activate.

If these work, then one by one add the plugins that you had until you find the one that broke it.

That’s what I had to do and now my site works fine.