Hi,
the second problem sounds like the same kind of issue I had ( http://kempwire.com/bb/topic/how-to-use-in-wordpress-mu ).
This plugin doesn't work in WordPress 3 at the moment.
There is a change to the way that WordPress records users role (admin/editor/contributor/subscriber) in the database.
New users are recorded in the new way, old users who have been imported are recorded the old way. This plugin is only displaying users that are recorded in the old way.
There isn't much to change, but do backup your site and database before making changes! But this might work for you as well.
Step 1 - edit the wpusers.php file.
There are two long lines that list all the types of users (admin/editor/etc.) You need to edit those two lines to add 4 characters :"1" to each type of user.
The first line should then read
$rolelist = array('\'a:1:{s:13:\"administrator\";s:1:"1";}\''=>$administrator, '\'a:1:{s:10:\"subscriber\";s:1:"1";}\''=>$subscriber, '\'a:1:{s:6:\"author\";s:1:"1";}\''=>$author, '\'a:1:{s:6:\"editor\";s:1:"1";}\''=>$editor, '\'a:1:{s:11:\"contributor\";s:1:"1";}\''=>$contributor);
The second should read
$roles = array('\'a:1:{s:13:\"administrator\";s:1:"1";}\'', '\'a:1:{s:10:\"subscriber\";s:1:"1";}\'', '\'a:1:{s:6:\"author\";s:1:"1";}\'', '\'a:1:{s:6:\"editor\";s:1:"1";}\'', '\'a:1:{s:11:\"contributor\";s:1:"1";}\'');
The Directory page should now show only newly created users, not the old ones. Which is the opposite of the way it was before.
Step 2 - Upgrade/Downgrade users
This should be fairly easy, especially if you only have a few users.
You need to make sure that WordPress is recording users in the new way (so that the plugin can identify them)
Log in and move all the users to another level and back to their original one (e.g. Subscriber->Contributor->Subscriber). You should see all users in the Directory now.
You may need to create a temporary administrator account for this, so that you can upgrade and downgrade your normal admin user.