If OMSA showed an IP address of 0.0.0.0, then either somebody set it that way, OMSA is not communicating with the DRAC, or there is something wrong with the DRAC.  If the "racadm setniccfg ..." command doesn't work then a good next step is reseating and reflashing the DRAC.
Is there any way to find the IP of a DRAC card without rebooting to the configuration screen?  We have one host we can't boot and would like to configure the card.
Find IP of DRAC Card