Hi,
Seems I recall someone having a problem enabling or disabling certain autoemail functions and a post from one of the Auctiva folks on there being a bug. I was looking around for the post and couldn't find it. However, I think they suggested opening a Support Case for them to do it manually for you until it was fixed.
Even if that's not correct, a Support Case is best way to get action on a bug/problem.
Danno