I'm getting this same error. Did you figure it out?
The following information may help you determine the form at issue:
Field/Xpath: /efile:Return[1]/efile:ReturnData[1]/efile:IRS1040[1]/efile:PYEarnedIncmAdditonalChldTxGrp[1]/efile:PriorYearEarnedIncomeAmt[1]
Checked prior year AGI a couple of times. It's correct. Also went as far to update Form 2441 and Form 8812 as I saw my spouses earned income may have been incorrect with some 1099-misc income with a self employment deduction. Those corrections did not fix the problem.
