@ socialteenz.....i explained above (if you read it) that i dont have a navigation menu and i did read that thread before asking this question
--------------- Added [DATE]1337867803[/DATE] at [TIME]1337867803[/TIME] ---------------
okay guys....this thread can be locked....i found which add-on was causing the trouble. It was hidden inside VBfoster-missing features (lite). When i disabled the add-on, it did not disable the activity stream....i dont know why. However, when i completely removed the add-on, it did get rid of the forum activity stream. That was weird !!!