server actions - - the To field is not evaluated

2012-02-14 17:57:29,958 2193 ERROR ? fetchmail: Failed to fetch mail from imap server mail.instantina crm
Traceback (most recent call last):
  File "/srv/openerp/instances/openerp_test_chricar/src/server/openerp/addons/fetchmail/fetchmail.py", line 195, in fetch_mail
    action_pool.run(cr, uid, [server.action_id.id], {'active_id': res_id, 'active_ids':[res_id]})
  File "/srv/openerp/instances/openerp_test_chricar/src/server/openerp/addons/base/ir/ir_actions.py", line 685, in run
    res_email = ir_mail_server.send_email(cr, uid, msg)
  File "/srv/openerp/instances/openerp_test_chricar/src/server/openerp/addons/base/ir/ir_mail_server.py", line 388, in send_email
    assert smtp_to_list, "At least one valid recipient address should be specified for outgoing emails (To/Cc/Bcc)"
AssertionError: At least one valid recipient address should be specified for outgoing emails (To/Cc/Bcc)

please see attachment
the help text is not clear if the object.mail_from has to be embedded in [[ ]] or not