I would start your poller using netapp-manager or netapp-worker with the -v flag to enable verbose logging. It logs a lot so you would then need to search through it (grep) for the nic_common stuff and/or new counters added to see what is happening. Keep in mind that Harvest does not submit metrics if the calculated value is 0, so it could also be that you have 0 errors between polling intervals and thus won't see a metric submitted. In verbose logging you will see the raw counter value and can see the computed value would be zero and is thus not sent to Graphite.
Cheers, Chris Madden
Solution Architect - 3rd Platform - Systems Engineering NetApp EMEA (and author of Harvest)