I have the same problem
but in my case the bb-config.php is in the same directory as wp-config but I still get the error message. also the bbpress forum does actually work, but it is just that buddypress cannot see it and does not work from within buddypress. My wordpress installation is in a folder not the root of the html docs
When you go to the section about installing bbpress it always files, to do with the location of bb-configure.php
