Situation
You attempt to delete an account with a zero balance from the Accounts List, but this message appears. This indicates that though the current balance is zero, there was activity and a non-zero balance at some time in the current or previous fiscal period.
Solution
You cannot delete the account at this time, but when you have had no balance or activity for two fiscal periods, you will be able to delete it.
Until you can delete it, if you don't want the account to appear on your Accounts List, you can mark the Inactive Account field in the Profile view of the Edit Accounts window.