I added the code into pp_checkout_failure.php as you suggested and went through the purchase sequence again.
However no additional messages were shown
I put the code into the body.
Any other ideas?
<h1>Transaction Not Completed</h1>
<p>Your PayPal transaction could not be completed. Please return to <a href="checkout.php">checkout</a> and try again.</p>
<?php echo $WA_PP_ECO_DoResult->fullRequest; ?>
<?php echo $WA_PP_ECO_DoResult->fullResponse; ?>
<!-- InstanceEndEditable -->