The Aged Receivables and Aged Payables report should always agree with their corresponding General Ledger Accounts.  Below are the most common reasons for discrepancies between the aging reports and their corresponding accounts.
  1. If the Beginning Account Balance for the AR (or AP) Account and the Customer (or Vendor) Beginning Balances (i.e. the outstanding invoices from before you started using Sage 50 (Peachtree)) were not equal, than the aging report and the account will not match.
  2. If any entries were posted to the AR account that did not originate in either Sales Journal (SJ) or Cash Receipts (CRJ) Journal, then the aging report and the account will not match.  Note: The Accounts Payable corresponding report would be Purchase Journal (PJ) or Cash Disbursements Journal (CDJ).
  3. If any invoices or Cash Receipts/Payments were posted to an account other than the AR (or AP) account, then the report and the account will not match.
To check #1, you can ask the question, did the Aging Report ever match the AR (or AP) account?  If they matched last month, focus on #2 and #3 above.  You can Preview or Print the General Ledger for the account and look at the Journal (Jrnl) column to find entries that are not from the appropriate journal.  For AR the Jrnl column should list SJ (Sales Journal) or CRJ (Cash Receipts Journal).  You can also view the Sales Journal and Cash Receipts Journal and look for entries that do not include the AP account.
If they never matched, focus on #1 and either put in the Customer Beginning Balances that are missing or adjust the AR account so that it matches the total of the Customer Beginning Balances (i.e. Outstanding Invoices).  A good source for this would be an Aging Report for the period immediately proceeding your start date in Sage 50 (Peachtree).