The erorror is due to not specifying the Warehouse in the Production order Details form or in Create Production Order form.
Since as per the Screenshot given, the Warehouse is marked as Active,Mandatory and Primary stocking in the Inventory Dimensions form of the Inventory management module form.
When the above said check box marked, the Warehouse has to be specified in the Inventory transactions(for example - Production order creation etc.,)
You either fill it in on the line or set the work centre consumption and have the production order drive this from the persepective of the consumption.