The Ironton Tribune in southern Ohio reports that a computer glitch caused owners of manufactured homes to receive a tax bill for the first half of the year for a second time instead of a bill for the final six months of 2011.  The tax bills for manufactured homes are exactly half each time.  The 4,998 manufactured homes in the county provide six percent of the tax revenue, comprising just under ten percent of the 55,000 parcels.  Taxpayers may contact the Lawrence County Treasurer’s office for the correct amount owing.  If they overpaid, they can either get a refund or apply the overage to next year’s tax bill.