Reject Codes S2-F1040-428 and S2-F1040-429 occur when the IRS database indicates that the taxpayer or spouse received a First Time Homebuyer Credit in a previous year and did not include the repayment amount on this year's return. If the first-time homebuyer credit was claimed by a taxpayer for a home that was purchased in 2008, repayment of the credit began with the 2010 tax return and continues for 15 years or when the house is sold, whichever is earlier. The amount that the IRS believes the taxpayer owes as installment payment can found at the IRS website for First Time Homebuyer Credit Lookup.