F1040-512 Each Dependent's SSN on this return cannot be used on another return as a Primary or Secondary SSN with Line 6a checkbox 'ExemptPrimaryInd' or Line 6b checkbox 'ExemptSpouseInd' checked on that return.
This reject means that the dependent was filed on a return either as a primary taxpayer or a secondary. If the dependent did not file a return or have knowledge of being secondary(spouse) on a return, they will need to contact the IRS. If so and it was a mistake and dependent should not have claimed them self, they may be able to file an amendment.
This information applies to all years of the UltimateTax software.