Sales tax major purchase deduction not working properly

When I enter the amount of sales tax paid on a major purchase, Turbo Tax Premier gives an error that the calculated rate does not match the rate for where I live ("Because of IRS regulations, you cannot deduct the sales tax paid on your Plumbing materials purchase because it was calculated using a rate that does not match the general rate for your location (0.0780)".)   Even when entering a dummy transaction of $1000, with 78 dollars of tax (a 7.8% rate) I get the error.