anti-splog problem

using 1.0.5 and wp 3.0.4

Just got an email from someone who could not activate his blog.
tried myself, error.
checked the error log and found anti-splog as the culprit, please help.

anti-splog is activated and set up like this:

here is the line from the error log when clicking the activate link the user gets via email:

[Thu Feb 17 13:55:30 2011] [warn] mod_fcgid: stderr: PHP Fatal error: Call to undefined function ust_wpsignup_url() in /var/www/clients/client1/web9/web/wp-content/themes/edu-clean/header.php on line 91

header.php looks like this: <div id="edublog-free"><h3>Fa-ti si tu un blog gratis cat ai clipi din ochi</h3><p><a href="<?php ust_wpsignup_url(); ?>" title="Fa-ti si tu un blog gratis cat ai clipi din ochi">Inregistreaza-te</a>

everythign was working, didn't change anything lately, just wondered why nobody signed up since I installed AVH First Defense Against Spam although I am not sure this is related. Didn't checl earlier since this is a small quiet community.