from reading the MSDN documentation It looks like username and password are only for overriding the user that is currently logged in, as I am logged in as a full administator this should not be the issue...But I shall try it and let you know.

EDIT: Yup, same results except now I get a message about not being able to use credentials for local system so that one no longer works =) Other than that the same few show up and the ones that kept returning nothing are still returning nothing...