F5 LTM SOAP API - Ruby f5-icontrol Gem - Could not find element by name: pool_names

I tried to update my question in IE and Chrome but when I hit save it's not doing anything--not sure what's going on. In any case, please note that I forgot to include the beginning "/" in get_all_member_statistics above (but my code is correct). Note that I also tried specifying the pool name in a number of different ways (e.g. "/Common/name-of-pool", "name-of-pool", an array of pool names (even though F5 docs suggest string), URL-encoded name-of-pool, etc.).