The software is operating correctly, the setting you turned off is for the actual who's online link
www.yoursite.com/forum/online.php not for displaying number of guests. This line
HTML Code:
<span class="shade">{vb:rawphrase x_members_and_y_guests, {vb:raw numberregistered}, {vb:raw numberguest}}</span>
in forumhome is what shows your numbers so maybe remove
HTML Code:
,{vb:raw numberguest}
the
, isn't a typo, remove that too!