You see this dialog box when you press the Enter registration code-button from the Unregistered Version dialog box.
This is the dialog box where you enter, or paste, the registration code received in an e-mail from Voith's CODE.
Ensure that you have selected and copied the registration code to the clipboard, and press the Paste-button. When done correctly, it will look like this:
Press OK to save the registration code, or press Cancel to abort the registration of List Fields.
When you press OK, you will see this confirmation message:
When you press OK in this dialog box, List Fields will terminate, and you have to start it again.