[ic] failpage not working

[Wojtek]

Hi:

I want to create a multi-page checkout from. But I can't get the 
mv_failpage working. I want to return to the same page when some fields 
are not filled out. But I am always forwarded to the next page 
("checkout-step2").

This is the form on my first fage:

<form action="[process]" method="post">
<input type=hidden NAME=mv_todo value=submit>
<input type=hidden NAME=mv_action        value=return>
<input type=hidden NAME=mv_nextpage      value="checkout-step2">
<input type=hidden NAME=mv_failpage      value="checkout-step1">
<input type=hidden name=mv_form_profile  value="check_this">

[set check_this]
	fname=required
	lname=required
	address1=required
	&fatal=yes
[/set]

What am I doing wrong?

Thanks in advance,
Wojtek