1. I had very similar situation: In my car (VW Passat) in the cars OBD connector wasn't pin 4, which goes to DB9 pin 1 (GND ground). So I connected together DB9 pins 1 and 2 (OBD 4 and 5).
Have You looked in OBDuino page?
Link:
OBDuinoInterface - opengauge - OBDuino OBD2 cable and Interfaces - Open Source Fuel Efficiency Instrumentation - Google Project Hosting
Link:
OBDuino32K - opengauge - Homepage of the OBDuino32K Project - Open Source Fuel Efficiency Instrumentation - Google Project Hosting
2. Which OBD protocol is used in yours car (Rover) it is necessary to check in internet?
From OBDuino page link:
OBD-2 Liste (erfolgreich) gescannter Fahrzeuge - Rover (2000 year) - ISO 9141-2
Best regards