Pager links not showing on paged project browsing results

When we have paged results when browsing projects using the new interface, the pager links aren't appearing at the bottom of the page. The relevant lines from project.module:

We use a pager_query, if appropriate.

      $pager = module_invoke($module, 'project_sort_methods', 'pager', $sort_method);
      if ($pager) {
        $first_field = array_shift($sql_elements['fields']['pieces']);
        array_unshift($sql_elements['fields']['pieces'], "COUNT($first_field)");
        $sql_count = project_build_query($sql_elements);
        $result = pager_query($sql, variable_get('default_nodes_main', 10), 0, $sql_count, $parameters);
      }

And at the bottom of the page:

  if ($pager) {
    $output .= theme('pager', NULL, variable_get('default_nodes_main', 10));
  }

But the pager links aren't there.