Unexpted Error when Receiving an Outsourced Manufacturing Purchase Order

We are exploring the possibility of starting to use the Outsource Manufacturing functionality for some of our eStores. In our Sandbox account, we have followed the instructions in the help files for Outsorced Manufacturing:

• We already had Purchase Orders, Advanced Receiving, and Assembly Items turned on.
• We turned on Multi-Location Inventory, Work Orders, and Advanced Bill of Materials
• We enabled Outsourced Manufacturing
• We created an outsourced manufacturing location for our test vendor
• We edited our vendor record to add the manufacturing location for the outsourcing vendor
• We created a Service for Purchase for that vendor and set the Cost Category to Outsourcing Charge