Maturity Differences

I don’t know set up of maturity differences. First, I post a sales order. Then I go to “accounts receivable → periodic → Maturity Differences”. When I want to calculated it, I got a error. It is about İnterest rate…by the way, I made some adjustment in billing codes and billing classifications according to interest rate. how can i exceed that problem??

Thanks for helping! ( I use Ax 2012 )