A/R question

[Cam Ellison]

When I first started my business, I created a number of A/R 
subaccounts.  Since everyone was paying on time, more or less, that 
meant I didn't need to use the Receivables Aging report, or not very 
much.  Things have changed, so in order to make proper use of Aging, I 
collapsed the subaccounts, and everything is now under the Receivables 
account.  However, now the credits don't match the debits, and the 
report is incorrect.

I'm sure this is going to mean going into 5+ years of data and making 
changes - but where do I make the changes?  What sort of transaction 
should I be looking for, and what should I change?  Re-entering and 
deleting won't cut it - a lot of the transactions have been reconciled.

TIA

Cam