Does this issue occur with 'any' type of disk you attempt to burn such as data disk (files & folders) .. including CD's not only dvd's?

If it were a mac I'd suggest a 3rd party app which forces the OS to recognise the burner (though that's supposedly not necessary for Leopard.)

For windows I wonder if the burner is in fact configured in the system as being recognised & used by burner programs. I recall from years back a similar issue & needed configuration in system hardware settings. (Sometimes you also need to set the burner program to choose which drive to use for burning in the burner's settings.) I'm not the best one to answer this but thought I'd get the ball rolling so to speak.