I found another bug which is related to fb_pathway.php (located under components/com_fireboard/templates/default/).
I had to change the code in the following way to make it work:
diff fb_pathway.php fb_pathway.php_ori
47,49c47,49
$results = $database->loadObject();
$parent_ids = $results->parent;
$fr_name = @trim($results->name);
---
> $results = $database->query();
> $parent_ids = @mysql_result($results, 0, 'parent'

;
> $fr_name = @trim(mysql_result($results, 0, 'name'

);
Without this changes the forum path isn't displayed properly (please note that the new code is lacking the diff specific minor sign because the editor used for this forum doesn't seem to like it)
Stephan