Robin W: I tried de-activating all the plugins, and it is BuddyPress (Version 2.1.1) which is causing the problem. Now what should I do about this? BuddyPress itself recommends bbPress to use it as forum, and not their plugin itself is not compatible with bbPress.
Robin W: Also, I would to like to tell you that before installing wp4 fix, the topics were not visible in the forum. Its only when I installed this fix, topics became visible.
Sorry for the late reply. I somehow had lost my login to bbpress.org forums.
Robin W: The problem was even before installing wp4 fix. Even after installing wp4 fix, it didn’t help.