'CMN.ATO.IITR.000257: Net non-Primary Production income/loss is incorrect. Non-PP - Net income or loss from business this year less Non-PP - Deferred non-commercial losses from a prior year does not equal Net non-Primary Production income/loss.
The error indicates that either:
there is a value at Item 15 Label C that is not equal to Item P8 (Label C - Label E) or
Item 15 Label C is blank and Item P8 (Label C - Label E) has a value greater than zero.
Example: Taxpayer has a value at Item 15 (Label C) $15,000 and Item P8 (Label C) $5,500 - (Label E) $500 = $5,000.
Example: To resolve the error for this taxpayer, we would need to enter $5,000 at Item 15.
Note: The following information is of a general nature. Contact the ATO for advice specific to your client's circumstances.