Ban IP and Block User forms not displaying

When I click on either button from Troll Track, I get a page with no content below the title. Examining HTML source code reveals, for IP Ban page:

<td valign="top">
            <div id="main">
        <!--<div class="breadcrumb"><a href="/">Home</a> » <a href="/admin">Administer</a> » <a href="/admin/user" title="Manage your site&#039;s users, groups and access to site features.">User management</a> » <a href="/admin/user/troll" title="Manage visitor IP banning.">Troll</a></div>-->
        <div class="node_format"> <h1 class="title">IP Ban Form</h1> </div>

        <div class="tabs"></div>
                        <form action="/admin/user/troll/ip_ban/user/1847"  accept-charset="UTF-8" method="post" id="troll-confirm-ban-ip-form">
<div><input type="hidden" name="form_token" id="edit-troll-confirm-ban-ip-form-form-token" value="3f8ef2414f1663353e04a476832bd30c"  />
<input type="hidden" name="form_id" id="edit-troll-confirm-ban-ip-form" value="troll_confirm_ban_ip_form"  />

</div></form>
              </div>
    </td>

No idea why this could be happening, have tried switching themes to no avail. Any suggestions? I can post a list of other installed modules if necessary, but the main Drupal version is the latest, and PHP, MySQL etc. are all recent stable Debian builds.