Causes
Ar row %1 a possible error is present, because the Gr indicated for the account is not the same as the Group in the totalization row.
In the example image, in the Group 40 are totalized the amounts of the rows having 40 as a Gr, but row 122 has 3 as a Gr.
This means that the account on row 122, in this case the account 3009 - Discounts on sales, will be totalized in the Group 3 and not into Group 40.
The program highlights the possible error, in case this structure hasn't been done on purpose.
It may not be a mistake
The amount of the account will be totalized in the indicated Group, no matter where the account row is placed in the accounting plan.
There are cases where a non-sequential disposition of the accounts is required, and it's therefore not a mistake.
Solution
Verify that all accounts listed and meant to be totalized in the same Group have the same Gr. More information are available at the Groups page.
We therefore suggest to correct your accounting plan indicating the same Gr for all the accounts that are to be totalized in the same Group.
In our example, the account 3009 - Discounts on sales, should have the Gr 40 and not 3.