ANOTHER UPDATE:
I fixed my problem with this plugin by modifying one line of it's code. The problem is caused by the fact that this plugin is not written to take into account users who have bbPress integrated with Wordpress and are sharing the user table. The plugin is hard-coded to use two tables called bb_users and bb_usermeta, which may not exist if you have a WP integrated setup sharing the user table.
So if you have the same problem, you can fix it by looking for this function in the plugin file moderator-notification.php (in version 1.0.1 of the plugin it starts at line 27):
function is_moderator($user_id) {
global $bbdb;
$mods = array('moderator', 'administrator', 'keymaster');
$is_mod = false;
$row = $bbdb->get_row("SELECT um.meta_value AS role
FROM bb_users AS u, bb_usermeta AS um
WHERE u.ID = um.user_id
AND um.meta_key = 'bb_capabilities'
AND u.user_status = 0
AND u.ID = $user_id
");
$arr = unserialize($row->role);
foreach($mods as $val) {
if (array_key_exists($val, $arr)) {
$is_mod = true;
break;
}
}
return $is_mod;
}
Modify this line:
FROM bb_users AS u, bb_usermeta AS um
to read:
FROM wp_users AS u, wp_usermeta AS um
OR whatever YOUR users and usermeta tables are named if different (they are MOST LIKELY wp_)
This worked for me, hopefully it will help someone else. I suggested to the plugin developer that he add an admin setting to let users designate the user table names since a lot of people use bbPress WITH Wordpress, and in my opinion this is a GREAT plugin once you get it working :)