Fix to this issue was given by staff member here:
http://www.oxwall.org/forum/topic/29249?&page=2
/ow_system_plugins/base/classes/event_handler.php
Replace following piece of code:
public function onAddMembersOnlyException( BASE_CLASS_EventCollector $event )
{
$event->add(array('controller' => 'BASE_CTRL_Join', 'action' => 'index'));
$event->add(array('controller' => 'BASE_CTRL_Join', 'action' => 'joinFormSubmit'));
$event->add(array('controller' => 'BASE_CTRL_Join', 'action' => 'ajaxResponder'));
$event->add(array('controller' => 'BASE_CTRL_Captcha', 'action' => 'index'));
$event->add(array('controller' => 'BASE_CTRL_Captcha', 'action' => 'ajaxResponder'));
$event->add(array('controller' => 'BASE_CTRL_User', 'action' => 'forgotPassword'));
$event->add(array('controller' => 'BASE_CTRL_User', 'action' => 'resetPasswordRequest'));
$event->add(array('controller' => 'BASE_CTRL_User', 'action' => 'resetPassword'));
$event->add(array('controller' => 'BASE_CTRL_User', 'action' => 'ajaxSignIn'));
$event->add(array('controller' => 'BASE_CTRL_ApiServer', 'action' => 'request'));
$event->add(array('controller' => 'BASE_CTRL_Unsubscribe', 'action' => 'index'));
$event->add(array('controller' => 'BASE_CTRL_BaseDocument', 'action' => 'redirectToMobile'));
by
public function onAddMembersOnlyException( BASE_CLASS_EventCollector $event )
{
$event->add(array('controller' => 'BASE_CTRL_Join', 'action' => 'index'));
$event->add(array('controller' => 'BASE_CTRL_Join', 'action' => 'joinFormSubmit'));
$event->add(array('controller' => 'BASE_CTRL_Join', 'action' => 'ajaxResponder'));
$event->add(array('controller' => 'BASE_CTRL_Captcha', 'action' => 'index'));
$event->add(array('controller' => 'BASE_CTRL_Captcha', 'action' => 'ajaxResponder'));
$event->add(array('controller' => 'BASE_CTRL_User', 'action' => 'forgotPassword'));
$event->add(array('controller' => 'BASE_CTRL_User', 'action' => 'resetPasswordRequest'));
$event->add(array('controller' => 'BASE_CTRL_User', 'action' => 'resetPassword'));
$event->add(array('controller' => 'BASE_CTRL_User', 'action' => 'ajaxSignIn'));
$event->add(array('controller' => 'BASE_CTRL_ApiServer', 'action' => 'request'));
$event->add(array('controller' => 'BASE_CTRL_Unsubscribe', 'action' => 'index'));
$event->add(array('controller' => 'BASE_CTRL_BaseDocument', 'action' => 'redirectToMobile'));
$event->add(array('controller' => 'BASE_CTRL_AjaxLoader', 'action' => 'init'));
$event->add(array('controller' => 'BASE_CTRL_AjaxLoader', 'action' => 'component'));
$event->add(array('controller' => 'BASE_CTRL_Avatar', 'action' => 'ajaxResponder'));