Warning: Questions regarding depreciating assets should be answered if deduction for decline in value of depreciating assets is greater than zero.

Answer: This is the warning and not the error. and ATO will accept it. however, due to ATO validation rules if entity is not SBE and field "Deduction for decline in value of depreciating assets" has value, then you optionally need to fill AT LEAST ONE of these fields:  

under "Depreciating assets first deducted in this income year":
- Intangible depreciating assets first deducted
- Other depreciating assets first deducted
- Have you self-assessed the effective life of any of these assets?
- Are you making a choice to opt out of temporary full expensing for some or all of your eligible assets?
- Number of assets you are opting out for?
- Value of assets you are opting out for?
- Temporary full expensing deductions
- Number of assets you are claiming for?
- Are you using the alternative income test?

 

under "For all depreciating assets":
- Did you recalculate the effective life for any of your assets this income year?
- Total adjustable values at end income year
- Assessable balancing adjustments on the disposal of intangible depreciating assets
- Deductible balancing adjustments on the disposal of intangible depreciating assets
- Termination value of intangible depreciating assets
- Termination value of other depreciating assets
- Subsequent year accelerated depreciation deductions for assets using Backing business investment