Hi ,
ihave installed free version for joomla cms.
only admin user is shows online
why no other user shows online whether they are online.
and one thing also - can its support to jomsocial alos

Yes, it support jomsocial, If you want to integrate it to jomsocial .

Go to freichat/hardcode.php and replace $driver='Joomla'; by $driver='JSocial';

Also, are you sure there are other users online? try opening two browsers and see if you can see eachother .