[Marten]

Yes, those errors can be hard to track down if your new to lisp. The problem in your file is that you have not named your local function and don't have any content in your ok-action:

    :local-functions '(    
        (create () 
            (sd-call-cmds    (create_workplane :new :name "Ring"))
        )
    )
    :ok-action '(create)

When you change to the code above your command loads without errors.

Regards,

Marten