POSIBLE SOLUTION TO YOUR PROBLEM
Hello ZOMACK1,
Since you have realflight Deluxe, Vol.1 & 2 work with Realflight Deluxe.
I think to run Vol.3 & 4 you need G2 upgrade.I read somewhere the Vol.3 will only run with the new G2 interlink or G2 interlink upgrade.
Check with the Greatplanes Techs and see what they say.
Good Luck
NEDYOB