When changing Order Status in Virtuemart you may see an error vmError: updateStatusForOneOrder unknown virtuemart_order_id which is caused by a small bug in the Virtuemart 4.0.4 package. It will be patched in the next version but in the meantime here's how you fix this Virtuemart Error.

vmError: updateStatusForOneOrder unknown virtuemart_order_id

Before you start, always remember to backup - make sure you have a verified backup of your Joomla Virtuemart software