Cannot Delete duplicated Purchase Order

Hi,

I inadvertently created two purchase orders for the one inventory item and turned them into bills. One bill has been paid but not the first one created.

The item cost is 70.07 and the Item Register display of the item shows;

Date Source Qty Amount On Hand Current Value

          PJ         1       70.07         1          70.07

          PJ         1       70.07         2         140.14 - so far so good...

          SJ        -1      -$82.44      1          57.70  - WTF! Where does this number come from?

          PJ         1         65.28       2         122.98 - yes, there was a cost reduction

         SJ         -1       -65.28       1          57.70

The Transaction Recap for the first SJ where the weird value appears, shows it correctly took 70.07 from Inventory (a 1- account) and offset that against Cost of Sales (a 5- account). So why is that item showing as 57.70 value on hand?

When I try to delete the first (unpaid) Purchase order, I get an error saying "Deletion of this sale of item (number) would value your inventory at less than $0.00" - well yes, because the PO has 70.07 value and the SOH has 57.70 value...

If I try to add an inventory line to the PO of Qty -1 value 57.70 and save the PO, I end up with Zero stock at Zero value, but the PO has a value of 12.37. If I try deleting the PO now, I get the same error as above!

How can I delete this PO without stuffing up my stock or GL?

Can I make a misc PO credit (not a stock item) and apply that to the PO to "cancel" it? But will that stuff up my GL?

This is all very frustrating and I'm hoping someone has a simple solution for me :-)

Cheers,

Philip