rejection error

Error message: Data in the return is missing or invalid. Please double check your entries.

Solution: The IRS has added a new requirement that every Installment sale both past and current must have the Installment Sale Property Type Code entered. Please verify that a valid selection has been made from the property type code table. NOTE: The property code is limited to values 1 through 4. If the property code on Form 6252, line 1, shows a number other than 1, 2, 3, or 4, please delete/remove the property code entry (or entries), click onto another field, and then verify the proper code is printed on the Form 6252. If the property code generates an incorrect code, please re-enter the code from the input field and select the correct code from the drop-down.

Code: /Return/ReturnData/IRS6252/InstallmentSalePropertyTypeCd

Anyone know how to resolve this?  I have checked the property codes and they are correct.  I do not know what I am missing.