Batch Job - Finalize Purchase orders

Hi, I have created a bacth job from Periodic activities to be able to finalize all PO invoiced. However, I have this message when I checked the log file as the batch is failed:" Purchase order PO-000141 cannot be finalized on 6/17/2014. The accounting date must be on or after the last accounting date 7/2/2014 that is used to account the purchase order". Any idea on why this happen?

What I have missed when I setup that job? Any idea is appreciated/ Thanks