You mentioned that you can see the invoices on the customer account, when you view the Transactions. What are the dates in these invoices? Are they later than the 'Calculate as of' date on the Aged Trial Balance report? If so, they they will not be included on the report, because 'Calculate as of' ignores future-dated transactions.

What is the Current Amount of each invoice? If it is zero (ie paid or credited) then it will not appear on the report either.

If you think that the invoices should have printed on the ATB report, let us know the invoices respective dates and current amounts, and the options selected for the report.