Although there is no technical problem with the switch setup, it would require two public IP addresses, and your cable company will likely charge a monthly fee for a second IP address.
If you have an old (non-wireless) router that is stable, try connecting it to the cable modem, with the OBi and the Netgear router (with latest firmware) connected to the old router.
It's possible that there are some settings changes that would allow the Netgear with currenct firmware to play nicely with the OBi. Router model and version? What services do you have on the OBi? What problems are you seeing?