I know there was some issues with leaving comments on the blog, and I believe all those have been fixed.
In case someone on the internets stumbles on this page (or I run into the same problem again), the solution is to add a function_exists around the gravatar div in comments.php template.
<?php if (function_exists(‘gravatar’)) {?>
<div class=”gravatar”>
<img src=”<?php gravatar(“R”, 40); ?>” alt=”Gravatar” />
</div>
<?php } ?>
If you have no idea what this means, then don’t worry about it.