FILE - This April 13, 2014, file photo shows the Internal Revenue Service (IRS) headquarters building in Washington. For small-business owners, preparing an income tax return is far from simple, which can increase the chances of making a mistake. According to two small-business pros, if you catch an error after you’ve filed your small-business tax return, the first thing to do is confirm there’s really an error on the return and make sure to stay calm. (AP Photo/J. David Ake, File)