Moved the imports from the top of the file into the task function. This seemed to prevent some strange import errors that only occurred on the production server. I don't know if the problems were related to mod_wsgi or Python 2.5 or what.

{% load url from future %}
{% if show_button %}
<a href="{% url 'forums-edit_post' id=post.id %}"><img src="{{ STATIC_URL }}icons/page_edit.png" alt="Edit post" title="Edit post" /></a>
{% endif %}