Packing Your Order Failed Due To: Input Source Not Set!
This error will occur when trying to submit an order and the image files have been moved or are no longer in the location they were when the order was created. Basically an image file is missing.
Look through the shopping cart for a product with a missing image or a white thumbnail
Open the order receipt and by clicking Show Receipt at the top of the cart and review as an alternative
Once the product is found, click on the edit product button on the product with the missing image (the pencil icon)
Reassociate the correct image to the product
Click the Save button to save the changes
Submit the order
If the above does not work then the order will need to be reviewed again
Make sure any external hard drives are properly mapped/plugged in before rebuilding