it's because you are set to invisible in your profile.. now you have also turned off letting users select that as an option, so those who are already invisible can't change it so they ARE visible..

so they'll stay invisible..

what you can do to see who is currently invisible is run this query:
SQL Query
select u.USER_DISPLAY_NAME from ubbt_USER_PROFILE up, ubbt_USERS u WHERE up.USER_VISIBLE_ONLINE_STATUS <> 'yes'
and u.USER_ID=up.USER_ID

you should notice some peeps (including you prolly) that are in that list.

soooooo, just run this query:
SQL Query
update ubbt_USER_PROFILE SET USER_VISIBLE_ONLINE_STATUS='yes' WHERE USER_VISIBLE_ONLINE_STATUS <> 'yes'

and that will force everyone to visible and then be included in who's online wink