If the customer is set up, in "Customer Entry" in ACCOUNTS RECEIVABLE (6.1.1 field 22 page 2), with <Y>es "PO Required?" then the cursor will stop at the Purchase Order field. You will not be able to continue without entering a Purchase Order number. Type in the Purchase Order number and press <ENTER>. Or the customer may be setup with a Blanket Purchase Order, in "Customer Entry" in ACCOUNTS RECEIVABLE (6.1.1 field 53 page 4), that will be automatically entered when starting a new order for this customer.