I'm going to guess that you are using your OBi on your LAN, it gets it's IP, gateway, and DNS via DHCP, you are specifying openDNS servers in your router, and your OBi will not function properly using openDNS. Is that it?
If so, you could just overide the DHCP assigned DNS in your OBi with one or two manual entries for either your ISP's DNS or some free ones like those of Level3: 4.2.2.2, 4.2.2.3
Or is there some advantage of using openDNS on your OBi?