Just a quick update:
BMW still has the car. The car decided to go into a "remission" so to speak and the error disappeared for a week so they could not test whether or not the new idrive controller would fix it. Yesterday during a test drive the shift lever malfunction came up again and they were able to get it hooked up to the computer while it was giving the error. They said that as soon as they unplugged the idrive controller, the error went away. They are installing a new one today and hopefully this nightmare will be over...