I have this problem.
There is error showing up on the jomsocial link :
Warning: call_user_func_array() [function.call-user-func-array]: First argument is expected to be a valid callback, 'CommunityModelActivities::getTotalActivities' was given in /home/hellohap/domains/website.xxx/public_html/components/com_community/libraries/core.php on line 1830
Please reply i am worried for this error and cannot find any solution. The jomsocial version is 2.xx