Postnuke Anyone ?

Hi, I've been unsuccesfully trying to add a php script to a postnuke menu. What I did is a simple form, that connects to a mysql database, and inserts data, then some data is retrieved to generate a page with "Welcome $name $lastname ... and so on" The problem is the script must be in the center and must include the header, the footer and the left block, I don't understand many things from the way postnuke works, and I couldn't display any variable entered in the form, neither insert data into the db ... I've tried with action="some.php" and action=<?php PHP_SELF?>; so far I only got parsing errors. Any ideas ? Regards, Rick