This appears to be a software bug, follow the steps below to resolve the problem.

1. Go to the Amended return input screen. 
2. Scroll down to the Federal Income Tax Return section.
3. The fourth line down is “Spouse SSN on original return when applicable”.   Ente the spouse’s SSN in this field.
4. Once that is done, click on the Return Actions in the upper right.
5. Then click on Customer Support Tools.   This will open up a matrix with all the inputs from this screen.
6. Scroll to the bottom and hit Edit. Then Continue.
7. Then find the line with the code 471.  You should see the SSN that you just entered at the end of that line.
8. Under the fourth column from the left, STATEID, enter MD.
9. Then hit Save in the lower right.