If it is asking for a State ID for a payer, then it is looking for the corresponding state to the exempt interest, i.e NY, CA, etc - not the amount. If your form doesn't make it clear which state it is, then enter "XX" - this should clear that error. Also, if you entered a zero in the original form, then the program may be trying to attach a state ID to a zero amount. So, if the XX doesn't clear that error, return to your dividends and remove any 0s and leave the item blank.