Why did H&R Block have to restate its earnings?

…the company said that it will restate its results for fiscal years 2005 and 2004, as well as previously reported quarterly results for fiscal 2006. The restatement pertains principally to errors in determining the company’s state effective income tax rate, resulting in a cumulative understatement of its state income tax liability of approximately $32 million as of April 30, 2005. The company estimates that the restatement will result in a 7-cent decrease in earnings per share in fiscal 2005 and a 2-cent decrease in earnings per share in fiscal 2004.

This kids, is the definition of Irony.