When I said that I couldn't change what was on Form 1099-R, I was approaching it from the perspective that what was shown on the screen in the box (16) that was blank was "grayed out" (i.e. it was not changeable, and could not be tabbed into from where the error was being described).
I subsequently went back to the input for "Income", and proceeded to the area where Form 1099-R was electronically imported from Fidelity, and saw that I WAS able to alter the number in Box 16 there, and save the result. Problem solved!!
I corresponded with the representative who I chatted with on line about this issue, and suggested that it would be prudent for Intuit to accompany the error message in situations like mine to suggest the fix - i.e. Instruct the user to access the form in the "Income" section of the application.
So my final hurdle is fixed, and I am giving my return one last look before filing electronically. I feel stupid for not thinking of the solution earlier myself, and I hope that my suggestion is helpful to others.
I want to thank everyone who responded to my question for your assistance!
