Is there anything at the remote site that can connect to the server at the "main office"? If not then you'll need to make sure you have setup your firewall rules to allow traversal between the sites. Are both sites using the same IP address range? Are the routers handling IP's or is the SBS server? If it's the SBS server, how is the remote server getting an IP address? My guess would be that both locations are using different subnets and the firewall rules haven't been established to allow traffic to go between the subnets.