Here is the solution
www.virtueplanet.com/vp-one-page-checkou...nect/index.php#18012
Under
public_html/plugins/system/vponepagecheckout/cart/tmpl
and I changed the lines under default_login.php like below;
before:
<h4 class="proopc-subtitle"><?php echo JText::_('PLG_VPONEPAGECHECKOUT_ASK_FOR_LOGIN'); ?></h4>
<form action="<?php echo $action_url; ?>" method="post" name="proopc-login" id="UserLogin" autocomplete="off">
after:
<h4 class="proopc-subtitle"><?php echo JText::_('PLG_VPONEPAGECHECKOUT_ASK_FOR_LOGIN'); ?></h4>
<div><p>{JFBCLogin}</p></div>
<form action="<?php echo $action_url; ?>" method="post" name="proopc-login" id="UserLogin" autocomplete="off">
looks fine...