Anti-Splog move signup page does not work

I am using Anti-Splog 1.1.1 with Multi-db 3.0.6 with 16 databases. I enabled the "Move wp-signup.php" option, I used the <?php ust_wpsignup_url(); ?> inside my page and it generate a new link like this: http://mydomain.com/signup-xxx/ but when I click on this signup link, it just load my homepage.

It does not show the signup form to register new blog.

Any solution?

By the way I've added add_global_table('ust'); into my db-config.php file as well.