I'm not certain which version of TurboTax you are using, but recently there was an update to the desktop versions. This may be part of the issue. If you use a desktop product, make sure to perform an update the next time you log back into your tax return.
If you received the First-Time Homebuyer Credit in 2008, then you need to complete Form 5405 to account for your $500 repayment amount.
You can confirm your repayment balance for the First-Time Home Buyer Credit by clicking this IRS link: First-Time Homebuyer Credit Account Look-up.