There are a couple of items that are braking the flow of MAMS:

1)
Registration Template 1:
{mod_action_url module=SelfRegistration action=default mode=sendanotheremail}

module=SelfRegistration


2) 

$this->RegisterRoute(
      '/[Mm]amsreg\/register\/(?P<returnid>[0-9]+)\/(?P<group>.*)$/',
      array('action' => 'signp')
    );
    $this->RegisterRoute(
      '/[Mm]amsreg\/confirm\/(?P<returnid>[0-9]+)\/(?P<mr_data>.*?)$/',
      array('action' => 'verify')
    );

should be:

    $this->RegisterRoute(
'/mams\/register\/(?P<returnid>[0-9]+)\/(?P<group>.*)$/', array('action'
=> 'signup')
    );
    $this->RegisterRoute(
'/mams\/confirm\/(?P<returnid>[0-9]+)\/(?P<mr_data>.*?)$/', array('action'
=> 'verify')
    );

signup was a typo and action register_link calls for $pretty_url =
"mams/register/{$returnid}/{$params['group']}";

hope this helps