Fatal error message after last comment

I moved my blog to another server to use my own domain and also changed the theme beacause Landzilla had some paragraph formatting on a few posts. i decided to use a customized version of Provision Public. Everything is almost fine, except for the following: when I clicck on a post and its page appears, the following message appears after the last comment:

Fatal error: Call to undefined function: commentscript() in /home/giovane/public_html/wp-content/themes/provision/comments.php on line 81

I don’t know if it is plugin error, it seems this theme uses some Gravatar plugin, but even if it is deactivated the error message still appears. I will reproduce the lines a think the message is referring to:

<?php if (‘open’ == $post->comment_status) : ?>
<!– If comments are open, but there are no comments. –>

<?php else : // comments are closed ?>
<!– If comments are closed. –>
<p class=”nocomments”>Comments are closed.

<?php endif; ?>
<?php endif; ?>

<?php if (‘open’ == $post->comment_status) : ?>
<?php commentScript() ?>
<h3 id=”respond”>Leave a Reply</h3>

What is the problem? Can someone help me, please?