So, I found that the following method works:
When asked about the apportionment, pick ANY category other than the top one and then open Forms and the 502A will appear in the left column. Open the form and remove the bogus selection you just made to make the for appear and then it will disappear from the left column, but you still have it open! Use the button below the form to delete the form. At this point, you should be able to file electronically without this error.
TurboTax, please FIX this problem! We pay enough for the product that this SHOULD NOT persist for years on end. I cannot imagine the total number of hours that have been wasted on this problem.
