The first time homebuyer credit in 2008 was an attempt to jump start the economy by helping people to buy a house. It was a credit of up to $7500, that has to be repaid $500 per yer over 15 years, or when you stop using the home as your main home, whichever comes first.
The rejection means that either you didn't make a payment the IRS thinks you owe, or you are trying to make a payment the IRS doesn't think you owe.
Did you buy a home in 2008 and claim the credit? If so, you need to make a payment now, or you need to report that you sold or moved out of the house.
If you did not get the credit in 2008, did you somehow claim you did so you are trying to make a payment you don't owe?