1099-R box 2B error

I have a 1099-R that is blank in box 2 and box 2B for "Taxable amount not determined" is checked. I entered the information this way on the desktop program but after completing the income section, it showed that I said the income on that 1099-R was not taxable. It is taxable. I don't know how to correct this unless I enter the same amount is box 2 that is in box 1, even though that's not what is on the 1099-R I received.  Any ideas?