Hi Maggie Miller:
Thanks for posting.
When you first install FileMaker Server, it will always have you setup an administrator account that will be used to log into the admin console. There is currently no option available in FileMaker Server that will allow you to disable the admin login, or set a saved username and password combination for subsequent logins.
The ability for saved logins would make for an excellent feature request, so I encourage you to submit a feature request at the following link.
I would copy the request for you, however the feature request form will ask you personal questions which you can only answer.