A million-dollar mistake has prompted a change in the state`s child support system. State officials described the change today while under intense questioning from lawmakers about how the mistake occurred. Over the Thanksgiving break, a state contractor double-issued 7,500 child support checks. The state is trying to recoup the money, but may never get it all back. Officials say the mistake occurred because the contractor downloaded the same payment list twice, causing a bank to issue the checks twice.