Purchase Order not found when based on Sales Order

[MacPhotoBiker]

Usually I create Purchase Orders "from scratch", but I do like the option to create them based on Sales Orders. Unfortunately, I get an error when doing so (and I tried several times). This is what I did:

1. Sales -> Enter an order ("Order number 1 has been entered")
2. Sales -> Outstanding Sales Orders -> Place PO ("Purchase order 1 has been created")
3. Purchases -> Purchase Orders -> Click on "Order # 1" -> Enter line items -> Process Order ("Purchase Order 1 has been updated") (I am aware that this step
4. Print Purchase Order -> "ERROR Message Report : Unable to Locate Purchase Order Number : 1"

I only seem to get this error when generating a Purchase Order based on a Sales Order, but not when I create a Purchase Order from scratch.