2010 Tax question. Received an AUR controll letter.?

I just received a letter from IRS saying that they adjusted my 2009 taxes . I forgot to include a W2 so I got to much of a refund for 2009.They said I did not need to amend 2009 just pay the overpayment amount.I am fixing to file my 2010 taxes and due a refund. Will they just hold what I owe out of my 2010 tax refund. Or do I need to pay before I file? This is for Mississippi.