1) The addon_whosonline.php included in the latest version (28 Jan 2007) package shows a last modified date of 17 April 2006. ??
2) The 'Attention' note in the readme for the who-is-online plugin instructs users to stick the who-is-online code close to the top of bb_plugins.php - immediately after <?php , unless CAPTCHA is also installed.
In a setup without CAPTCHA installed, should the bb_plugins.php read like so [excluding the line numbering, of course]:
line 1: <?php
line 2: if (!defined('INCLUDED776')) die ('Fatal error.');
line 3: include($pathToFiles.'addon_whosonline.php');
If memory serves, line 2 was a recommended addition from some time ago - I assume it is still required?
EDIT: I should have posted my query relating to the readme to the who's online addon thread instead of here. Apologies!