[BSMedia]

// ############################### start do login ###############################
// this was a _REQUEST action but where do we all login via request?
if ($_POST['do'] == 'login')
{
	$vbulletin->input->clean_array_gpc('p', array(
		'vb_login_username'        => TYPE_STR,
		'vb_login_password'        => TYPE_STR,
		'vb_login_md5password'     => TYPE_STR,
		'vb_login_md5password_utf' => TYPE_STR,
		'postvars'                 => TYPE_BINARY,
		'cookieuser'               => TYPE_BOOL,
		'logintype'                => TYPE_STR,
		'cssprefs'                 => TYPE_STR,
	));

	// can the user login?
	$strikes = verify_strike_status($vbulletin->GPC['vb_login_username']);

	if ($vbulletin->GPC['vb_login_username'] == '')
	{
		eval(standard_error(fetch_error('badlogin', $vbulletin->options['bburl'], $vbulletin->session->vars['sessionurl'], $strikes)));
	}

	// make sure our user info stays as whoever we were (for example, we might be logged in via cookies already)
	$original_userinfo = $vbulletin->userinfo;

	if (!verify_authentication($vbulletin->GPC['vb_login_username'], $vbulletin->GPC['vb_login_password'], $vbulletin->GPC['vb_login_md5password'], $vbulletin->GPC['vb_login_md5password_utf'], $vbulletin->GPC['cookieuser'], true))
	{
		($hook = vBulletinHook::fetch_hook('login_failure')) ? eval($hook) : false;

		// check password
		exec_strike_user($vbulletin->userinfo['username']);

		if ($vbulletin->GPC['logintype'] === 'cplogin' OR $vbulletin->GPC['logintype'] === 'modcplogin')
		{
			// log this error if attempting to access the control panel
			require_once(DIR . '/includes/functions_log_error.php');
			log_vbulletin_error($vbulletin->GPC['vb_login_username'], 'security');
		}
		$vbulletin->userinfo = $original_userinfo;

		if ($vbulletin->options['usestrikesystem'])
		{
			eval(standard_error(fetch_error('badlogin_strikes', $vbulletin->options['bburl'], $vbulletin->session->vars['sessionurl'], $strikes)));
		}
		else
		{
			eval(standard_error(fetch_error('badlogin', $vbulletin->options['bburl'], $vbulletin->session->vars['sessionurl'])));
		}
	}

	exec_unstrike_user($vbulletin->GPC['vb_login_username']);

	// create new session
	process_new_login($vbulletin->GPC['logintype'], $vbulletin->GPC['cookieuser'], $vbulletin->GPC['cssprefs']);

	// do redirect
	do_login_redirect();

}
else if ($_GET['do'] == 'login')
{
	// add consistency with previous behavior
	exec_header_redirect($vbulletin->options['forumhome'] . '.php');
}

Thats the part that deals with the cookies right?

Thanks for your help, this should get us at least on the correct path again