I was going to dig out my old EEPROM files this morning but it looks like you got it going.
When I started mine up for the first time after installing the oil sending unit, I thought it wasn't working properly because the meter just pegged at 5 and didn't move. After a few miles it settled down and started working properly. It looks like that's pretty standard, although that's probably not what's happening with Kevin if it had worked before and then stopped.
To isolate the sending unit as the problem, you can unplug the wire to the cluster, and then measure the resistance with an ohm meter between the metal body of the sending unit and the terminal you unplugged the wire from. With the engine off it should read an open circuit (infinite). With the car running and warmed up, it should read roughly between 15 and 90 ohms, depending on RPM. As you rev the engine, the resistance should change. I would probably do that first before spending the $90 on a new unit.
Benjamin