[fci]

Found a bug:
if your includes/config.php has its db type set to mysqli, it breaks registration, e.g:

$config['Database']['dbtype'] = 'mysqli';

To fix it, you need to update the register_addmember_process under Manage Products to the following:

//if the cookie exists then we know that the user already has an account
if (isset($_COOKIE['IDstack']) && $vbulletin->options['marpon'])
{
	//set the usergroup to the one specified in options, or Users Awaiting Moderation
	$userdata->set('usergroupid', $vbulletin->options['marpusergroup']);
	
	//Automatic banning of previously banned users
	if ($vbulletin->options['marpautobanon'] && $vbulletin->options['marpbannedgroup'])
	{
		$marpautoban = FALSE;
		if($idstack = explode(',',$_COOKIE['IDstack']))
    {
			foreach ($idstack as $uid)
			{
				if (is_numeric($uid))
				{
					//check to see if any of the multiple users are banned
					if (is_member_of(fetch_userinfo($uid), $vbulletin->options['marpbannedgroup']))
						$marpautoban = TRUE;
				}
			}
			
			//ban the user
			if ($marpautoban)
				$userdata->set('usergroupid', $vbulletin->options['marpbannedgroup']);
		}
	}
}
//IP based prevention
else 
{
	if ($vbulletin->options['marpipon'])
	{
		$ip = $_SERVER['REMOTE_ADDR'];
		
		//check to see if another user exists with the same ip address
		if ($multip = $vbulletin->db->query_read("SELECT userid,username,ipaddress FROM " . TABLE_PREFIX . "user WHERE ipaddress='{$ip}'"))
		{
			if ($vbulletin->db->num_rows($multip) > 1)
			{
				$userdata->set('usergroupid', $vbulletin->options['marpusergroup']);
				
				$andids = " ". $vbulletin->userinfo['username'] ." ";
				$andusers = $vbulletin->userinfo['username'];
				
				while ($mip = $vbulletin->db->fetch_array($multip))
				{
					$andids .= ', ' . " ". $mip['username'] ." ";
					$andusers .= ','.$mip['username'];
				}
				$message = construct_phrase($vbphrase['marp_ipmessage'], htmlspecialchars_uni($vbulletin->userinfo['username']), $andids, $ip);
				$subject = construct_phrase($vbphrase['marp_subject'], htmlspecialchars_uni($vbulletin->userinfo['username']), $andusers, '[IP]');
	
	      // get admin users
	      $adminusers = split(",", $vbulletin->options['ae_adminusers']);
	      $fromuser = fetch_userinfo($vbulletin->options['ae_sender']);
	      $allowsmilie = '1';
	      $visible = '1';
	      
	      // create the DM to do error checking and insert the new PM (needs to be here)
	      $pmdm =& datamanager_init('PM', $vbulletin, ERRTYPE_SILENT);
				$ipaddress = $vbulletin->config['ae_adminip'];
	
	      if($vbulletin->options['ae_sendpm'] == '1')
	      {
	          $pmdm->set('fromuserid', $fromuser['userid']);
	          $pmdm->set('fromusername', $fromuser['username']);
	          $pmdm->set_info('reciept', false);
	          $pmdm->set_info('savecopy', false);
	          $pmdm->set('title', $subject);
	          $pmdm->set('message', $message);
	          $pmdm->set_recipients($vbulletin->options['ae_recipients'], $fromuser['permissions']);
	          $pmdm->set('dateline', TIMENOW);
	          $pmdm->save();
	      }
	
	      if($vbulletin->options['ae_startthread'] == '1' AND $vbulletin->options['ae_forumid'])
	      {
	          require_once(DIR . '/includes/class_dm_threadpost.php');
	
	          // setup variables
	          $forumid = $vbulletin->options['ae_forumid'];
	          $threaddm = new vB_DataManager_Thread_FirstPost($vbulletin, ERRTYPE_STANDARD);
	              
	          // insert thread
	          $threaddm->do_set('forumid', $forumid);
	          $threaddm->do_set('userid', $fromuser['userid']);
	          $threaddm->do_set('username', $fromuser['username']);
	          $threaddm->do_set('pagetext', $message);
	          $threaddm->do_set('title', $subject);
	          $threaddm->do_set('allowsmilie', $allowsmilie);
	          $threaddm->do_set('visible', $visible);
	          $tid = $threaddm->save();
	
	          require_once(DIR . '/includes/functions_databuild.php');
	          build_forum_counters($forumid);
	      }
	    }
		}
		
	}
}

it is changing "mysql_num_rows($multip)" to "$vbulletin->db->num_rows($multip)"