Program keeps prompting me to enter the value in box 16 of my 1099-R but there is no value in the box on the form. Should I enter the state tax withheld amount box 14?

If you have state tax withheld in Box 14, enter that only in Box 14. In Box 16 enter the same number that is in box 2a of your 1099.  If there is no  number in 2a, use the number in Box 1.