Yeah..a couple ideas.
1) Edit the 1099-INT, and make sure boxes 15-16-17 are entirely blank. no 0,00, and hilite each box and hit the delete key to make sure nothing is there, not even a space.
2) IF not that, try deleting the 1099-INT and entering it again manually...(especially if the original was imported)
or
3)Maybe...if box 8 of the 1099-INT had $$ in it...maybe the error is referring to indicating what state(s) the box 8 $$ of exempt-interest came from......that information is provided by you on one of the pages following the main form. (Usually "Multiple States" from the end of the states list...unless you want to break out your own state's bond interest from the others )
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*