Aaaaah....I see.
I was putting the target=blank in the header ("Location: http://www.xyz.com target=blank");
and not in the form.
If you can help me with the next, similar problem, I'd be grateful.
How do you get the new page to print in a javascript pop-up window?
For instance,
<form action="geturl.php" method="post" onSubmit="NewWindow(this.href, '800', '600', 'no');return false">
with the appropriate javascript function preceding it.
However, I get a 404 error, whereas with target="blank", the page is correctly called.
Thanks again.