functions.php
'U_CHAT_ROOMS' => append_sid("{$phpbb_root_path}chat-room.$phpEx"),
viewonline.php right after case 'viewonline':
case 'chatrooms':
$location = $user->lang['CHAT_ROOMS'];
$location_url = append_sid("{$phpbb_root_path}chat-room.$phpEx");
break;
common.php
'CHAT_ROOMS' => 'Chat Rooms',
and Who is online still just shows it as being at the Index page at domain.com/index.php .