There are two possibilities if the service administrator isn't available in SuccessWare21:
First, you host your own LAN and are not logged on to a workstation directly connected to the SuccessWare21 server. Accessing the http service administrator does require this to be the case. To solve this, determine which workstation is connected to the server and login with your admin credentials.
Second, you require an API activation from SuccessWare21.
Follow the directions outlined here to get an API activation.
Call SuccessWare21 for more information on API activations at 1-888-251-2779