Help- does anyone know the protocols (type of OB11 system) for the above RRS.

I have a Code reader OBD11,EOBD & CAN BUS .It says it is designed to work with all OBD11 compliant vehicles including those with the CAN protocol.
BUT it keeps coming up with the message 'Linking Error' and suggests contacting your customer service department.
Any help appreciated. 2006 4.2 S/C with Tow Pack, Side Steps, DRL's, 19" & 20" wheels, additional 110 ltr Fuel Tank Roof Rack and performance mods.

1952 Rover 75 (Cyclops) First Car !!! Fond memories -was restored-good for 93mph.