Details received. Thank you!
There is only one entry your log file, and s2Member logged the following important snippet.
'ipn_track_id' => '5335e3d0bdef5',
's2member_log' =>
array (
0 => 'IPN received on: Sun Jan 13, 2013 10:12:19 pm UTC',
1 => 's2Member POST vars verified through a POST back to PayPal®.',
2 => 's2Member originating domain ( `$_SERVER["HTTP_HOST"]` ) validated.',
3 => 's2Member `txn_type` identified as ( `web_accept|subscr_signup` ).',
4 => 's2Member `txn_type` identified as ( `web_accept|subscr_signup` ) w/ update vars.',
5 => 'Unable to modify Subscription. The existing User ID is associated with an Administrator. Stopping here. Otherwise, an Administrator could lose access.',
),
This indicates that you ran a test transaction while being logged in as an Administrator of the site. Please log out of your site before testing what a customer will see.
See also: Knowledge Base » Testing User/Member Perspectives
Please let us know if problems persist :-)