I just setup WordPress and Enfold theme,
and install only bbPress plugin then activate it,
create a new page with forum shortcode.
But I got “ERROR: Are you sure you wanted to do that?” message when I what to create a new topic.
Mac OS X 10.8.4
Bitnami MAMP stack 5.4.9-0
Try switching to one of the default WordPress themes and see if the issue continues to happen. If so, the you will have better help from the bbPress support directly since we only add some additional styling for bbPress but don’t actually do any development for it.