You will need to go back over the Home Office section and be sure to answer "No" to the question that asks if you have more than one home office.
If this is a Job-related expense (meaning it is for a job which you get a Form W-2 from), then this is entered by clicking on the Federal Taxes tab, Deductions & Credits, scroll down to Employment Expenses, then click update next to Job-Related Expenses. Click edit on the next screen and continue through to the Home Office Summary screen, one this screen be sure you only have one home office listed, if there are more than one, then you will need to delete the one that should not be there. Click edit next to the Home Office address and continue back through this section until you get to "Did you have more than one home office?"
If this is for your own business, Click on the Business tab > Business Income and Expenses and click update, Scroll down to Business Expenses and click update next to Home Office Expenses, and go back over this section, be sure to answer "No" to the question "Did you have mote than one home office".