Cause of error:

The Sales / Purchase Ledger has "Inventory values are affected" option set as No".


Solution:

Set the "Inventory values are affected" to Yes for the Sales/Purchase ledgers.


Steps

1. Go to Gateway of Tally 

2. Select option "Accounts Info >> Ledger >> Alter"

3. Select the Sales/Purchase ledger

4. Set the value for option "Inventory values are affected" to Yes

5. Press Ctrl+A to save it.