Adding client computers to SBS 2003

Hello,

We just moved our administrative offices from one location to another, and with that, I moved the server and the 3-4 PCs we had to the new location. I have been able to re-connect all of them back up to the network and internet, but have been having problems connecting the 3 PCs that were already in the new location. I have tried to follow the help files I have found as well as the SBS 2003 book, but have not been able to get this done. After I add a new computer client account using the Server Management wizard tools, it tells me to go to http://(servername)/ConnectComputer, but I get the following error message: "YOU ARE NOT AUTHORIZED TO VIEW THIS PAGE.
The Web server you are attempting to reach has a list of IP addresses that are not allowed to access the Web site, and the IP address of your browsing computer is on this list." I have even set the TCP/IP Properties on the computer I'm trying to add to "Obtain IP address automatically". I realize as well that I'm supposed to do this while signed on as a user with administrative rights. How do I do that if it doesn't give me this option when I turn on the computer?

Can anyone tell me what I'm doing wrong?