Closing comments here, because the plugin now has its own page.

I’ve found a bug inside the code:

Being blog-admin and clicking the “Manage subscriptions”-link will result in an URI which has [...].php?&ref=[...]

So I digged through the code and changed the “manage_link”-function inside the “subscribe-to-comments.php”-file to the following:

function manage_link($email=”, $html=true, $echo=true)
{
$link = get_bloginfo(‘wpurl’) . ‘/wp-subscription-manager.php?’;

if ($html)
$amp = ‘amp;’;

$link .= ‘ref=http://’ . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'];

if($email != ‘admin’)
$link .= ‘&’ . $amp . ‘email=’ . $email . ‘&’ . $amp . ‘key=’ . md5($email . DB_PASSWORD);

if ($echo)
echo $link;
else
return $link;
}

HTH,
Martin..