PHP function?

I’ve been trying to put the petition form on my static homepage (index.php) but the function doesn’t work:

<?php echo dk_speakup_emailpetition_shortcode('1'); ?>

But it doesn’t load the CSS or JavaScript necessary for the form to function (read thread http://wordpress.org/support/topic/plugin-speakup-email-petitions-php-code).

So is it possible to make the PHP function work somehow?

Thanks for your help!

https://wordpress.org/plugins/speakup-email-petitions/