"the software required for this iPhone is not installed correctly. Please reinstall itunes...

for context, i have two memory storages, the smaller being system C.

system D is where i had selected iTunes to be installed (system C was almost completely full and wouldn't accept my library), but there is a discrepancy i am not able to control. i have undone the full program three times already but no success. i should also bring to notice that the only devices this does not occur with are the two ipod nanos. the touch, iPad and iPhone all do this error message.