For a shopping cart/product configuration to go through the approval process correctly, you need to have approval values available from the Status field.

To add values to the Status picklist

  1. From Setup, go to Create > Objects and click Product Configuration.
  2. From Custom Fields & Relationships, click Status.
  3. From Picklist Values, click New and add Approval Required and Pending Approval.
  4. Click Save.

These values will now be available from the Status picklist for a Product Configuration object record, which also means the status can appear in the Status field at the top left of the Shopping Cart.