For the Whos_online look the posting above your's.If you change this the user is not shown if he is in the hidden forum
for the search problem you forget something in the hack
######################
# ubb_search.cgi open #
######################
#########
#find : #
#########
if ($forum_info[6] eq 'private') {
################
# replace with #
################
if (($forum_info[6] eq 'private')||($forum_info[6] eq 'hidden')) {
#########
#find : #
#########
if ($get_path[6] eq 'private') {
################
# replace with #
################
if (($get_path[6] eq 'private')||($get_path[6] eq 'hidden')) {